Answer:
The ambient temperature is 35°C.
It takes 15 minutes to cool the substance from 40°C to 35°C.
Explanation:
Using Newton's Law of Cooling to answer the given problem.
[tex]\boxed{\left\begin{array}{ccc}\text{\underline{Newton's Law of Cooling:}}\\\\ \frac{dT}{dt} =-k(T-T_a)\end{array}\right}[/tex]
Given:
The time it takes to cool from 50°C to 45°C = 3 minutes
The time it takes to cool from 45°C to 40°C = 5 minutes
Find:
Time ambient temperature and the time it takes to cool the substance from 40°C to 35°C
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(1) - Using first initial condition:
[tex]\text{Avg temp =} \ \frac{50+45}{2}=\boxed{47.5 \textdegree C}\\\\\Longrightarrow \frac{50-45}{3}=-k(47.5-T_a) \\\\\Longrightarrow \boxed{ \frac{5}{3}=-k(47.5-T_a)}[/tex]
(2) - Using the second initial condition:
[tex]\text{Avg temp =} \ \frac{45+40}{2}=\boxed{42.5 \textdegree C}\\\\\Longrightarrow \frac{45-40}{5}=-k(42.5-T_a) \\\\\Longrightarrow \boxed{1=-k(42.5-T_a)}[/tex]
(3) - Now we have a system of equations.
[tex]\left \{ \frac{5}{3}=-k(47.5-T_a)}} \atop {1=-k(42.5-T_a)}}} \right.[/tex]
(4) - Solve the system by dividing the top equation by the bottom equation.
[tex]\Longrightarrow \frac{\frac{5}{3}=-k(47.5-T_a)}{1=-k(42.5-T_a)} \\\\\Longrightarrow\frac{5}{3}=\frac{47.5-T_a}{42.5-T_a}\\ \\ \Longrightarrow 5(42.5-T_a)=3(47.5-T_a)\\\\\Longrightarrow 212.5-5T_a=142.5-3T_a\\\\\Longrightarrow 2T_a=70\\\\\therefore \boxed{T_a=35 \textdegree C}[/tex]
Thus, the ambient temperature is 35°C.
(5) - Find the value of "k" using either of the two previous equations
[tex]1=-k(42.5-T_a)\\\\\Longrightarrow 1=-k(42.5-35)\\\\\Longrightarrow 1=-7.5k\\\\\Longrightarrow \boxed{ k \approx -0.133}[/tex]
(6) - Now finding "dt"
[tex]\text{Avg temp =} \ \frac{40+35}{2}=\boxed{37.5 \textdegree C}\\\\\Longrightarrow \frac{40-35}{dt}=0.133(37.5-35) \\\\\Longrightarrow \frac{5}{dt}=0.3325\\\\\therefore \boxed{dt \approx15 \ min}[/tex]
Thus, it take 15 minutes to cool the substance from 40°C to 35°C.
In heating coil of resistance 20ohms, Connected to a 220 volts Source is used to boil a in Certain quantity of water container of heat Capacity 100j/k for 2 minute, If the initial temp. of water is 40°c. Calculate the mass of water in the container (4.2x10³j/k =SHC of water) Assume 100°c of water.
The mass of water in the container is approximately 115.38 kg.
To calculate the mass of water in the container, we can use the formula:
Q = mcΔT
Where:
Q is the heat energy transferred to the water,
m is the mass of the water,
c is the specific heat capacity of water, and
ΔT is the change in temperature.Given:
Resistance of the heating coil (R) = 20 ohms
Voltage (V) = 220 volts
Time (t) = 2 minutes = 2 * 60 seconds = 120 seconds
Specific heat capacity of water (c) = 4.2 x 10^3 J/kg°C
Change in temperature (ΔT) = 100°C - 40°C = 60°C
First, we need to calculate the heat energy transferred to the water using the formula:
Q = IVt
Where:
I is the current flowing through the heating coil.
Using Ohm's Law, we can find the current:
I = V/R
I = 220 V / 20 ohms
I = 11 A
Now, we can calculate the heat energy:
Q = (11 A) * (220 V) * (120 s)
Q = 290,400 J
Substituting the values into the formula for heat energy:
290,400 J = (m) * (4.2 x 10^3 J/kg°C) * (60°C)
Simplifying the equation:
m = 290,400 J / (4.2 x 10^3 J/kg°C * 60°C)
m ≈ 115.38 kg
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In the Buoyancy experiment, the weight of a cylinder (Wac) is found to be 4 N. When immersed in water the apparent weight of the cylinder (Wap) is 3.8 N. The Buoyancy force exerted by water on the cylinder is
The buoyant force exerted by the water on the cylinder is 0.2 N.
To find the buoyancy force exerted by water on the cylinder, we need to understand the concept of buoyancy and Archimedes' principle.
Archimedes' principle states that the buoyant force acting on an object immersed in a fluid is equal to the weight of the fluid displaced by the object. The buoyant force opposes the weight of the object and is responsible for the apparent loss of weight when an object is submerged in a fluid.
In this experiment, the weight of the cylinder (Wac) is 4 N. When the cylinder is immersed in water, the apparent weight of the cylinder (Wap) is 3.8 N. The difference between these two weights is the buoyant force exerted by the water on the cylinder.
Buoyant force (B) = Wac - Wap
B = 4 N - 3.8 N
B = 0.2 N
Therefore, the buoyant force exerted by the water on the cylinder is 0.2 N.
This means that the upward force exerted by the water on the cylinder is 0.2 N, opposing the downward force of gravity. The buoyant force depends on the volume of the fluid displaced by the object. In this case, the weight of the displaced water is equal to the buoyant force, as stated by Archimedes' principle.
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As a general rule, which of the following characteristics of planets decreases as their distance from the Sun increases?
A. Diameter
B. Gravitational Pull
C. Length of Orbit
D. Temperature
Temperature of planets decreases as they distance from the Sun increases.
What is temperature?Temperature serves as a physical quantity used to express our perception of hot or cold sensations. Thermometers are used as instruments for measuring this quantity accurately across various scales--each scale utilizing different reference points and materials historically.
A noteworthy fact regarding planetary climates is their dependence on received amounts of solar radiation: planets situated farther away from the sun tend to have lower overall temperatures because they receive less direct sunlight.
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Example A 0.050 kg ingot of metal is heated to 200.0°C and then dropped into a calorimeter containing 0.400 kg of water initially at 20.0°C. The final equilibrium temperature of the mixed system is 22.4°C. Find the specific heat of the metal.
Solution Energy leaves the hot ingot and goes into the cold water, so the ingot cools off and the water warms up. Once both are at the same temperature , the energy transfer stops.
The specific heat of the ingot of metal heated and then dropped into a calorimeter is 100.0 J/kg°C.
How to calculate specific heat?The heat lost by the ingot is equal to the heat gained by the water.
Q_ingot = Q_water
The heat lost by the ingot can be calculated as follows:
Q_ingot = m_ingot × c_ingot × (T_ingot - T_f)
The heat gained by the water can be calculated as follows:
Q_water = m_water × c_water × (T_f - T_water)
where:
m_ingot = mass of the ingot (0.050 kg)
c_ingot = specific heat of the ingot (to be determined)
T_ingot = initial temperature of the ingot (200.0°C)
T_f = final equilibrium temperature (22.4°C)
m_water = mass of the water (0.400 kg)
c_water = specific heat of water (4.184 J/g°C)
T_water = initial temperature of the water (20.0°C)
Substituting these values into the equations:
m_ingot × c_ingot × (T_ingot - T_f) = m_water × c_water × (T_f - T_water)
or
c_ingot = (m_water × c_water × (T_f - T_water)) / (m_ingot × (T_ingot - T_f))
Plugging in the values:
c_ingot = (0.400 kg × 4.184 J/g°C × (22.4°C - 20.0°C)) / (0.050 kg × (200.0°C - 22.4°C))
c_ingot = 100.0 J/kg°C
Therefore, the specific heat of the metal is 100.0 J/kg°C.
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An aircraft is flying south west at 250 m/s. There is a crosswind due East at 75m/s.
a) Draw the vector diagram and the resultant vector.
b) Calculate the magnitude of the resultant vector.
c) Calculate the angle to the resultant.
d) State the magnitude and direction of the resultant vector.
A) These vectors should be drawn with the appropriate scale and labeled. The resulting vector is obtained by adding the two vectors head-to-tail. The tail of the crosswind vector should be connected to the head of the aircraft velocity vector.
B) R ≈ √68125 m/s ≈ 260.98 m/s
C)θ ≈ arctan(0.3)
θ ≈ 16.7°
D)The magnitude of the resultant vector is approximately 260.98 m/s. The direction of the resultant vector is approximately 16.7° south of west.
a) To draw the vector diagram, we represent the velocity of the aircraft as a vector pointing southwest with a magnitude of 250 m/s. We also represent the crosswind as a vector pointing east with a magnitude of 75 m/s. These vectors should be drawn with the appropriate scale and labeled. The resulting vector is obtained by adding the two vectors head-to-tail. The tail of the crosswind vector should be connected to the head of the aircraft velocity vector. The resulting vector represents the resultant velocity.
b) To calculate the magnitude of the resultant vector, we can use the Pythagorean theorem. Let's denote the magnitude of the resultant vector as R. The magnitude of the aircraft velocity vector is 250 m/s, and the magnitude of the crosswind vector is 75 m/s. Therefore,
R^2 = (250 m/s)^2 + (75 m/s)^2
R^2 = 62500 m^2/s^2 + 5625 m^2/s^2
R^2 = 68125 m^2/s^2
Taking the square root of both sides, we find:
R ≈ √68125 m/s ≈ 260.98 m/s
c) To calculate the angle to the resultant, we can use trigonometry. Let's denote the angle between the resultant vector and the southwest direction as θ. We can use the inverse tangent function:
tan(θ) = (75 m/s) / (250 m/s)
θ ≈ arctan(0.3)
θ ≈ 16.7°
d) The magnitude of the resultant vector is approximately 260.98 m/s. The direction of the resultant vector is approximately 16.7° south of west.
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Abbas of mass 1000 kg is moving with velocity 25 m per second what is the amount of force required to stop the bus in 5 second
Force of a body is calculated by mass times acceleration.
Acceleration = Velocity/Time
= 25/5
= 5 m/s²
Now,
Force = 1000 × 5
Force = 5000 N
Hence, 5000 N force is required to stop the bus in 5 second
The force required to stop the bus is 5000 N.
Explanation:Given:
Mass of the bus (m) = 1000 kgInitial velocity (v) = 25 m/sTime taken to stop (t) = 5 secondsFinal velocity (v') = 0 m/sAcceleration (a) can be calculated using the formula:
a = (v' - v) / t
Substituting the given values, we have:
a = (0 - 25) / 5 = -5 m/s²
The force required to stop the bus can be calculated using Newton's second law of motion:
F = ma
Substituting the mass and acceleration, we get:
F = 1000 kg * (-5 m/s²) = -5000 N
Since the force cannot be negative, the magnitude of the force required to stop the bus is 5000 N.
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What is the resistivity of a wire of length 100cm and diameter 0.3mmis found as 3.0ohm
The resistivity of the wire of length 1 m and resistance of 3 ohm is 2.12×10⁻⁷ Ω/m.
What is resistivity?Resistivity is defined to the electrical resistance of a conductor of a particular unit cross-sectional area and unit length.
To calculate the resistivity of the wire, we use the formula below
Formula:
σ = RA/L......................... Equation 1Where:
σ = Resistivity of the wireA = Cross sectional area of the wireL = Length of the wire.From the question,
Given:
R = 3 ohmsL = 100 cm = 1 mA = πd²/d = (3.14×0.0003²)/4 = 7.065×10⁻⁸ m²Substitute these values into equation 1
σ = (3×7.065×10⁻⁸)/1σ = 2.12×10⁻⁷ Ω/mLearn more about resistivity here: https://brainly.com/question/30934104
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Why is it important for scientist to be skeptical
Answer:
I don't actually know, but it has to do with the research they id
Explanation:
to seem precise
A laser beam in the air (giving the index of refraction of the air is 1.00) is incident at the angle 30.0o from the vertical onto a solution of corn syrup in water. If the angle of refraction of the laser beam is 19.24o. What is the index of refraction of the syrup solution?
Select one:
a. 0.66
b. 1.14
c. 1.25
d. 1.52
Answer:
c
Explanation:
A student librarian lifts a 2.2-kg book from the floor to a height of 1.25 m. He carries the book 8.0 m to the stacks and places the book on a shelf that is 0.35 m above the floor. How much work does he do on the book?
The work done by the pupil librarian on the book is equal to the change in implicit energy of the book.
First, we need to calculate the implicit energy of the book when it's on the bottom
Ep1 = mgh1 = (2.2 kg)(9.81 m/ s2)( 0 m) = 0 J
where m is the mass of the book, g is the acceleration due to graveness, and h1 is the original height of the book( on the bottom).
Next, we need to calculate the implicit energy of the book when it's on the shel
f Ep2 = mgh2 = (2.2 kg)(9.81 m/ s2)(0.35 m) = 7.637 J
The total work done by the pupil librarian on the book is the difference in implicit energy
W = Ep2- Ep1 = 7.637 J- 0 J = 7.637 J
So the pupil librarian does 7.637 J of work on the book.
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PHYSICS QUESTION PLEASE HELP AND SHOW WORK :) - A car of mass 990 kg drives around a curve of radius 30 m. If the car maintains a constant velocity of 12 m/s, what is the centripetal force acting on the car?
Answer: The centripetal force acting on the car is 4752 Newtons
Explanation:
The formula for centripetal force (F) is:
[tex]F = m * v^2 / r[/tex]
where:
m is the mass,
v is the velocity, and
r is the radius.
Given that the mass (m) of the car is 990 kg, the velocity (v) of the car is 12 m/s, and the radius (r) of the curve is 30 m, we can substitute these values into the formula:
[tex]F = 990 kg * (12 m/s)^2 / 30 m[/tex]
Solving this gives:
[tex]F = 990 kg * 144 m^2/s^2 / 30 m[/tex]
This simplifies to:
[tex]F = 4752 N[/tex]
Therefore, the centripetal force acting on the car is 4752 Newtons.
If the height of an object is doubled, the potential energy will
OA. increase by 4 times
OB. decrease by 1/2
OC. stay the same
O D. double
SUB
The height of the object, given that the potential energy of the object doubled will be double (option D)
How do i determine the height of the object?First, we shall list out the given parameters. Details below:
Initial potential energy (PE₁) = PInitial volume height (h₁) = hNew potential energy (PE₂) = 2PNew volume height (h₂) = ?Potential energy is given as:
PE = mgh
Keeping mg constant, we have
PE₁ / h₁ = PE₂ / h₂
Inputting the given parameters, we have
P / h = 2P / h₂
Cross multiply
P × h₂ = h × 2P
Divide both sides by P
h₂ = (h × 2P) / P
h₂ = h × 2
h₂ = 2h
Thus, we can conclude that the new height of the object will also double (option D)
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A football is kicked straight up into the air 19.62 m it hits the ground 4 seconds later with what speed did it leave the kickers foot 
The football left the kicker's foot with an initial vertical speed of 19.62 m/s.
The initial vertical velocity of a football kicked straight up into the air can be calculated using the kinematic equation:
v_f = v_i + a*t
where v_f is the final velocity (0 m/s in this case, as the football stops at its highest point before falling), v_i is the initial velocity (which we want to find), a is the acceleration due to gravity (-9.81 m/s^2, negative because it acts downward), and t is the time taken to reach the highest point.
First, we need to determine the time taken to reach the highest point, which is half of the total time (4 seconds):
t = 4 seconds / 2 = 2 seconds
Now we can substitute the values into the equation:
0 m/s = v_i - 9.81 m/s^2 * 2 seconds
Rearrange the equation to solve for v_i:
v_i = 9.81 m/s^2 * 2 seconds = 19.62 m/s
Therefore, the football left the kicker's foot with an initial vertical speed of 19.62 m/s.
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PLEASE HELP and show work, thank you !!
-The top speed of a Utahraptor is about 9 m/s. How long would it take a Utahraptor to run 1500 m if it accelerates from rest to 9 m/s? Assume acceleration is constant and it reaches its top speed at exactly 1500 m from its starting point.
Answer:
2.94 s
Explanation:
v = u + at
where:
v = final velocity = 9 m/s
u = initial velocity = 0 m/s (rest)
a = acceleration
t = time taken to reach final velocity
We can rearrange the equation to solve for time:
t = (v - u) / a
Substituting the given values, we get:
t = (9 m/s - 0 m/s) / a
Now, we need to find the acceleration. We can use another kinematic equation:
s = ut + (1/2)at^2
where:
s = displacement = 1500 m
u = initial velocity = 0 m/s
a = acceleration
t = time taken to cover the displacement
We can rearrange the equation to solve for acceleration:
a = 2(s - ut) / t^2
Substituting the given values, we get:
a = 2(1500 m - 0 m) / (1500 m / 9 m/s)^2
Simplifying, we get:
a = 3.06 m/s^2
Now, we can substitute this value of acceleration in the earlier equation to find the time taken:
t = (9 m/s - 0 m/s) / 3.06 m/s^2
Simplifying, we get:
t = 2.94 s
Object A attracts object B with a gravitational force of 10 newtons from a given distance. If the distance between the two objects is doubled, what is
the new force of attraction between them?
OA 2.5 newtons
B.
OC.
D.
5 newtons
20 newtons
100 newtons
Given that the original force is 10 newtons, the new force when the distance is doubled would be 2.5 newtons. Option A
What does Newton's law say?Based on Newton's law of gravitation, the force of gravity between two objects is inversely proportional to the square of the distance between them.
What this means is that if the distance between two objects is doubled, the force of gravity between them is reduced by a factor of four.
In this case, the distance between the two objects is doubled, so the force of gravity between them is reduced from 10 newtons to 2.5 newtons.
We can calculate it by saying 10 N / 4 = 2.5 N.
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Answer: A.
2.5 newtons
Explanation: edmentum
You are a sound engineer working on a music festival and need to calculate the speed of sound in the air. You measure the distance between the sound source and a microphone to be 10 meters and the time it takes for the sound to reach the microphone to be 0.05 seconds. What is the speed of sound in the air? (Units: speed - meters per second (m/s), distance - meters (m), time - seconds (s))
2 You are an electrician w orking on a circuit. You need to calculate the electric current flowing through a wire with a resistance of 10 ohms and a voltage of 50 volts. What is the electric current flowing through the wire? If the wire has a length of 10 meters and a cross - sectiona l area of 0.5 square meters, what is the electric conductivity of the wire? (Units: current - amperes (A), resistance - ohms (Ω), voltage - volts (V), length - meters (m), cross - sectional area - square meters (m^2), electric conductivity - siemens per mete r (S/m))
The electric conductivity of the wire is 0.05 siemens per meter (S/m).
To calculate the speed of sound in the air, you can use the formula:
Speed of sound = Distance / Time
In this case, the distance is 10 meters and the time is 0.05 seconds:
Speed of sound = 10 m / 0.05 s = 200 m/s
Therefore, the speed of sound in the air is 200 meters per second (m/s).
To calculate the electric current flowing through a wire, you can use Ohm's Law:
Current = Voltage / Resistance
In this case, the voltage is 50 volts and the resistance is 10 ohms:
Current = 50 V / 10 Ω = 5 A
Therefore, the electric current flowing through the wire is 5 amperes (A).
To calculate the electric conductivity of the wire, you can use the formula:
Electric conductivity = 1 / Resistance * (Cross-sectional area / Length)
In this case, the resistance is 10 ohms, the length is 10 meters, and the cross-sectional area is 0.5 square meters:
Electric conductivity = 1 / 10 Ω * (0.5 m^2 / 10 m) = 0.05 S/m
Therefore, the electric conductivity of the wire is 0.05 siemens per meter (S/m).
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Coulomb's law describes the force that occurs between any two charged
particles. How does Coulomb's law change if two like charges are changed to
two charges that have opposite signs?
before
+q
+q
after
+q
-q
11
OA. Neither the magnitude nor the direction of the force changes.
B. Both the magnitude and the direction of the force changes.
OC. The magnitude of the force is the same, but it changes from
repulsive to attractive.
OD. The magnitude of the force is the same, but it changes from
attractive to repulsive.
SUBMIT
Answer: Coulomb's law states that the force between two charged particles is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Mathematically, it can be represented as:
F = k(q1q2)/r^2
where F is the force, q1 and q2 are the charges of the particles, r is the distance between them, and k is the Coulomb's constant.
In the before scenario, both charges are positive (+q and +q), so they repel each other and the force between them is positive.
In the after scenario, one charge is positive (+q) and the other is negative (-q), so they attract each other and the force between them is negative.
Therefore, the correct answer is option C: The magnitude of the force is the same, but it changes from repulsive to attractive. The magnitude of the force is not affected by the sign of the charges, only the direction of the force changes.
Explanation: :)
scientific notation is useful in scientific calculation give reason
Answer:
to shorten the answer
or it's like a code because scientists already know what it means
Physics question and Please show work :)
Which has greater inertia, you or a skyscraper? If you push on the side of a skyscraper with a force of 100 N, how much force does the skyscraper push back on you with?
Answer:
Skyscraper
Explanation:
A human has less inertia than a skyscraper. The ability of matter to resist changes in motion is known as inertia, and it is inversely proportional to mass. A building has more inertia than a person since it has a larger mass.
According to Newton's third law of motion, if you apply a force of 100 N to the side of a skyscraper, the structure will respond by applying an equal and opposing force of 100 N to you. This is due to the fact that the force you exert on the tower is transmitted through your body, to your feet, and then into the ground. The skyscraper experiences an equal and opposite force from the earth, which is reflected back up your body through your feet.
Which of the following is not an effect that might have originated via catastrophic collision?
Uranus has an axial tilt of 98° with respect to its orbit.
The Moon of Earth is extremely large and only slightly younger than Earth itself.
Venus has an extremely high surface temperature, in fact, the highest on average of any planet in the solar system.
Mercury's crust is extremely small compared to the size of its nickel-iron core.
Some moons of Neptune possess retrograde or highly eccentric orbits.
B, Venus has an extremely high surface temperature, in fact, the highest on average of any planet in the solar system is not an effect that might have originated via catastrophic collision.
What describes a catastrophic collision?This is not an effect that might have originated via catastrophic collision. Venus's high surface temperature is due to its thick atmosphere, which is composed mostly of carbon dioxide. The carbon dioxide traps heat from the sun, causing the planet to warm up.
The other effects listed are all possible effects of catastrophic collisions. Uranus's axial tilt of 98° with respect to its orbit could have been caused by a collision with another planet-sized object.
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The speed of a wave is 2 m/s, and its wavelength 0.4 meters. What is the period of the wave? (1 point)
2 seconds
0.2 seconds
5 seconds
0.8 seconds
Answer: 0.2 seconds
Explanation: I took the test
The time period of the given wave is 0.2 seconds.
The speed of the wave, v = 2 m/s
The wavelength of the wave, λ = 0.4 m
The time period of a wave is defined as the amount of time required for one full oscillation in the medium's density.
It may alternatively be described as the amount of time needed for two successive rarefactions or compressions (Trough and Crest, respectively) to pass a given point.
The expression for the velocity of the wave is given by,
v = fλ
So, the frequency of the wave is,
f = v/λ
f = 2/0.4
f = 5 Hz
The time period of the wave can also be defined as the reciprocal of the frequency.
So, the time period of the wave is,
T = 1/f
T = 1/5
T = 0.2 s
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1.6 A B D A learner standing at a roadside records the frequency of sound waves produced by the siren of an ambulance. The ambulance is moving at constant velocity along a straight horizontal road. The frequency-time graph for the detected sound is shown below. Time (s) Which ONE of the following statements concerning the motion of the ambulance is CORRECT? C Detected frequency The ambulance ... (ZH) approaches the learner and then passes the learner. moves away from the learner, then turns and approaches the learner. approaches the learner, then turns and moves away from the learner. moves away from the learner and then stops. (2)
The correct answer to this question is option A, which indicates that the ambulance approaches the learner and then passes the learner.
Based on the information provided in the question, we can determine that the sound waves produced by the siren of an ambulance are detected by a learner standing at a roadside. The frequency-time graph shown in the question indicates that the detected frequency of the sound waves increases and then decreases over time. This suggests that the ambulance is moving towards the learner and then moving away from the learner. Option A in the question suggests that the ambulance approaches the learner and then passes the learner, which is consistent with the interpretation of the frequency-time graph. Therefore, option A is the correct answer. It is important to note that the question specifies that the ambulance is moving at constant velocity along a straight horizontal road. This means that the ambulance is not turning, which eliminates options B and C as possible answers. Option D suggests that the ambulance moves away from the learner and then stops, which is inconsistent with the information provided in the question.
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If a wave transfers from one medium to another medium with different properties, which statement is true? (1 point)
The frequency changes, while the wavelength and the speed of the wave remain the same.
The period and the speed of the wave change proportionally.
The period changes, while the wavelength and the speed of the wave remain the same.
The frequency remains constant.
Answer:
The frequency must be constant to maintain continuity the boundary.
Explain how the increase in need for energy is causing environmental damage. Give several solutions to this ongoing problem.
Answer: The increase in the need for energy is causing significant environmental damage in several ways like fossil fuels, land use, deforestation, water use, and Air and water pollution
Explanation:
The increase in the need for energy is causing significant environmental damage in several ways like in fossil fuels from where the majority of our energy comes from non-renewable sources such as coal, oil, and gas, which release harmful greenhouse gases into the atmosphere when burned, contributing to climate change and global warming.
Land use and deforestation increase the production of biofuels and the construction of power plants requires a significant amount of land, leading to deforestation and habitat loss.
Water uses in energy production consume vast amounts of water, leading to water scarcity and ecosystem degradation
Air and water pollution in the production and transportation of energy and the disposal of waste from energy production result in air and water pollution that harm both humans and wildlife.
To address these issues, we must focus on reducing our energy consumption, promoting renewable energy sources, and implementing energy-efficient practices. Here are several solutions to this ongoing problem:
Promote Renewable Energy: Increase the use of renewable energy sources such as solar, wind, and hydropower, which are cleaner and less harmful to the environment than fossil fuels.
Improve Energy Efficiency: Encourage energy-efficient practices such as using LED lights, insulating buildings, and using energy-efficient appliances, which can significantly reduce energy consumption.
Encourage Conservation: Promote energy conservation, such as turning off lights when not in use, using public transportation, and carpooling, to reduce the need for energy production.
Develop Sustainable Infrastructure: Create sustainable infrastructure such as green buildings and eco-friendly transportation, which reduces the need for energy production and minimizes environmental impact.
Implement Environmental Policies: Governments can implement environmental policies that encourage energy conservation and the use of renewable energy sources, such as incentives for renewable energy and carbon taxes on fossil fuels.
Promote Education: Educate the public on the importance of energy conservation and the benefits of renewable energy, which can lead to behavior change and a reduction in energy consumption.
In conclusion, the increase in the need for energy is causing significant environmental damage, but there are several solutions to this ongoing problem. By promoting renewable energy, improving energy efficiency, encouraging conservation, developing sustainable infrastructure, implementing environmental policies, and promoting education, we can minimize our impact on the environment while still meeting our energy needs.
PLEASE HELP WITH THESE TWO QUESTIONS- SHOW WORK ! THANK YOU !
For a projectile fired at 28 degrees from a height of 0 m, how long does it take to hit the ground? Remember that a_y=-9.8 m/s^2. Initial velocity of the projectile is 42 m/s. And second question is - using your answer from that above question, how far did the cannonball travel in the horizontal direction?
Answer:
4.06 seconds
148.3 meters
Explanation:
To solve for the time it takes for the projectile to hit the ground, we can use the following kinematic equation:
y = y_0 + v_0y * t + 1/2 * a_y * t^2
where y is the final height (0 m), y_0 is the initial height (also 0 m), v_0y is the initial vertical velocity, and a_y is the acceleration due to gravity (-9.8 m/s^2).
First, we need to find v_0y, the initial vertical velocity:
v_0y = v_0 * sin(theta) = 42 m/s * sin(28 degrees) ≈ 19.6 m/s
Now, we can solve for the time it takes to hit the ground:
0 = 0 + 19.6 m/s * t + 1/2 * (-9.8 m/s^2) * t^2
Simplifying and solving for t, we get:
t ≈ 4.06 seconds
Therefore, it takes about 4.06 seconds for the projectile to hit the ground.
To find the horizontal distance traveled by the projectile, we can use the following kinematic equation:
x = v_0x * t
where x is the horizontal distance traveled, v_0x is the initial horizontal velocity, and t is the time it takes to hit the ground (which we just calculated).
Since there is no air resistance, the horizontal velocity remains constant throughout the motion. Therefore:
v_0x = v_0 * cos(theta) = 42 m/s * cos(28 degrees) ≈ 36.5 m/s
Now, we can plug in the values to find the horizontal distance traveled:
x = 36.5 m/s * 4.06 s ≈ 148.3 meters
different between word equation and formula equation
Answer:A word equation uses words to represent the reactants and products in a chemical reaction. A formula equation uses chemical symbols or formulas, but does not reveal the ratios of the products and reactants.
Explanation: example of a word equation: Synthesis, magnesium + chlorine → magnesium chloride.
Example of a formula equation:CH4(g) + O2(g) → CO2(g) + H2O(g)
Help please ! QUESTION 3
If a projectile is fired at 0° from the top of a 100 m building, how long will it take to hit the ground? Assume the initial velocity
of the projectile is 30 m/s.
g= -9.8 m/s²
3.33 s
33 s
20.4 s
4.52 s
Answer:
Approximately [tex]4.52\; {\rm s}[/tex], assuming that air resistance on the projectile is negligible.
Explanation:
It is given that the initial velocity of the projectile was [tex]u = 30\; {\rm m\cdot s^{-1}}[/tex] with an angle of elevation of [tex]0^{\circ}[/tex]. Decompose this initial velocity into its horizontal and vertical components:
Horizontal component of initial velocity: [tex]u_{x} = u\, \cos(0^{\circ}) = 30\; {\rm m\cdot s^{-1}}[/tex].Vertical component of initial velocity: [tex]u_{y} = u\, \sin(0^{\circ}) = 0\; {\rm m\cdot s^{-1}}[/tex].Under the assumptions, the duration of the free fall depends only on the vertical component of initial velocity, [tex]u_{y} = 0\; {\rm m\cdot s^{-1}}[/tex].
Apply the following SUVAT equation to find this duration:
[tex]\displaystyle x_{y} = \frac{1}{2}\, a_{y}\, t^{2} + u_{y}\, t[/tex],
Where:
[tex]x_{y} = (-100)\; {\rm m}[/tex] is the vertical displacement of the projectile, [tex]a_{y} = g = (-9.8)\; {\rm m\cdot s^{-2}}[/tex] is the vertical acceleration of the projectile,[tex]t[/tex] is the duration of the free fall, and[tex]u_{y}[/tex] was the initial vertical velocity of the projectile.Since initial vertical velocity was [tex]u_{y} = 0\; {\rm m\cdot s^{-1}}[/tex], this equation simplifies to:
[tex]\displaystyle x_{y} = \frac{1}{2}\, a_{y}\, t^{2}[/tex].
Rearrange this equation to find duration [tex]t[/tex]:
[tex]\begin{aligned}t &= \sqrt{\frac{2\, x_{y}}{a_{y}}} \\ &= \sqrt{\frac{2\, (-100)}{(-9.8)}}\; {\rm s} \\ &\approx 4.52\; {\rm s}\end{aligned}[/tex].
Answer:
The last option, t=4.52 s.
Explanation:
The following information will help you tackle any projectile motion problem (assuming there is zero air friction), so please read carefully.
This projectile motion problem is solvable with some basic knowledge of projectile physics and the use of the 4 kinematic equations that are written below.
[tex]\boxed{\left\begin{array}{ccc}\text{\underline{The 4 Kinematic Equations:}}\\\\1. \ \vec v_f=\vec v_0+\vec at\\\\2. \ \Delta \vec x=\frac{1}{2}(\vec v_f-\vec v_0)t\\\\3. \ \Delta \vec x=\vec v_0t+\frac{1}{2}\vec at^2\\\\ 4. \ \vec v_f^2=\vec v_0^2+2\vec a \Delta \vec x \end{array}\right}[/tex]
Things to note about the above kinematic equations:
In order to use the above equations, two things MUST be true.
i. Acceleration is constant.
ii. You must know at least three pieces of information.
When dealing with 2-D motion, NEVER mix horizontal and vertical components together in the same equation.
Tackling Projectile Motion Problems:
To tackle any projectile motion problem, you will have to split components up into x and y. I personally like to make a table which you will see later as I am solving the question.
Things that are true for all 2-D projectile motion problems:
[tex]\boxed{\left\begin{array}{ccc}\text{\underline{Horizontal Component:}}\\\vec a_x= 0 \ m/s^2\\ \vec v_x=\vec v\cos\theta\end{array}\right} \ \boxed{\left\begin{array}{ccc}\text{\underline{Vertical Component:}}\\\vec a_y= -9.8 \ m/s^2\\\vec v_y=\vec v\sin\theta\end{array}\right}[/tex]
The horizontal component of velocity will be the same throughout the projectiles flight while the vertical component of velocity is variable (always changing). The horizontal component of acceleration will always be zero while the vertical component of acceleration will be the acceleration due to gravity. These things are crucial to understand when dealing with projectile motion problems.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Given:
[tex]\vec v_o=30 \ m/s \ at \ 0 \textdegree\\\\\Delta \vec y= -100 \ m[/tex]
Find:
[tex]t= ?? \ s[/tex]
(1) - Splitting up what we know into it horz. and vert. components
[tex]\boxed{\left\begin{array}{ccc}\text{\underline{Horizontal Component:}}\\\vec a_x= 0 \ m/s^2\\ \vec v_{0x}=(30)cos(0 \textdegree)= 30 \ m/s\\\vec v_{fx}= ?? \ m/s\\ \Delta \vec x= ?? \ m\end{array}\right} \ \boxed{\left\begin{array}{ccc}\text{\underline{Vertical Component:}}\\\vec a_y= -9.8 \ m/s^2\\\vec v_{0y}=(30)sin(0 \textdegree)=0 \ m/s\\\vec v_{fy}= ?? \ m/s\\ \Delta \vec y= -100 \ m\end{array}\right}\\\\t=?? \ s[/tex]
(2) - As you can see from the table above we know three pieces of information for the vertical components. I will use equation 3 to solve for the time, t
[tex]\Delta \vec y=\vec v_{0y}t+\frac{1}{2}\vec a_yt^2\\\\\Longrightarrow -100=(0)t+\frac{1}{2}(-9.8)t^2\\\\\Longrightarrow -100=-4.9t^2\\\\\Longrightarrow t^2=20.4082\\\\\Longrightarrow t=\sqrt{20.4082} \\\\\therefore \boxed{\boxed{t \approx 4.52 \ s}}[/tex]
Thus, it takes about 4.52 seconds for the projectile to hit the ground.
Prove that when B , ℓ , and v are not mutually perpendicular, motional emf is given by emf=Bℓvsinθ . If v is perpendicular to B , then θ is the angle between ℓ and B . If ℓ is perpendicular to B , then θ is the angle between v and B .
This proves that the motional emf is given by the following equation, emf = Bℓvsinθ when B , ℓ , and v are not mutually perpendicular.
How to prove motional emf?The motional emf is the voltage that is generated when a conductor moves through a magnetic field. The magnitude of the motional emf is given by the following equation:
emf = Bℓvsinθ
where:
B = magnetic field strength
ℓ = length of the conductor
v = velocity of the conductor
θ = angle between the magnetic field and the velocity of the conductor
If v is perpendicular to B, then θ is the angle between l and B. If l is perpendicular to B, then θ is the angle between v and B.
The magnitude of the electric current is given by the following equation:
I = nqvA
where:
n = number of electrons per unit volume
q = charge of an electron
v = velocity of the electrons
A = cross-sectional area of the conductor
The electric current creates a voltage across the conductor, which is given by the following equation:
V = IR
where:
R = resistance of the conductor
The resistance of the conductor is given by the following equation:
R = ρl/A
where:
ρ = resistivity of the conductor
Substituting equations 2, 3, 5, and 6 into equation 1, gives following equation:
emf = Bℓvsinθ
This proves that the motional emf is given by the following equation:
emf = Bℓvsinθ
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How can you use graphs to calculate the displacement of an object?
Graphs can be used to calculate the displacement of an object by analyzing the relationship between time and position (or distance) on the graph.
Here's how:Position-Time Graph: If you have a position-time graph, the displacement of an object can be calculated by finding the difference between the initial and final positions. The displacement is equal to the change in position between two points on the graph. It can be determined by subtracting the initial position from the final position. The direction of displacement can be inferred based on the slope of the graph.Velocity-Time Graph: If you have a velocity-time graph, the displacement can be calculated by finding the area under the curve. The area under the graph represents the distance traveled, and the displacement is equal to the net area (taking into account the direction). Positive areas above the time axis represent displacement in one direction, while negative areas below the time axis represent displacement in the opposite direction.By utilizing these graphing techniques, one can analyze the position and motion of an object and calculate its displacement accurately. Graphs provide a visual representation of the relationship between time and position, allowing for a more intuitive understanding of displacement.
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Two learners want to confirm the principle of conservation of momentum for an isolated system. Two trolleys, with identical dimensions, but masses m and 1/2m, with a spring- loaded plunger between them, are placed on a horizontal surface. When the spring is released, it takes trolley X only 0.5 s to reach the barrier, which is 100 mm away. Trolley Y takes the same time to cover 200 mm to the other barrier. 1. Calculate the average speeds of trolleys X and Y respectively. 2 Calculate the total momentum after the release of the spring.
a) , the average speed of trolley X is 0.2 m/s and the average speed of trolley Y is 0.4 m/s.
b) the total momentum after the release of the spring is 0.4m kg·m/s.
To calculate the average speeds of trolleys X and Y, we can use the formula:
Average speed = Distance / Time
For trolley X:
Distance = 100 mm = 0.1 m
Time = 0.5 s
Average speed of trolley X = 0.1 m / 0.5 s = 0.2 m/s
For trolley Y:
Distance = 200 mm = 0.2 m
Time = 0.5 s
Average speed of trolley Y = 0.2 m / 0.5 s = 0.4 m/s
Therefore, the average speed of trolley X is 0.2 m/s and the average speed of trolley Y is 0.4 m/s.
To calculate the total momentum after the release of the spring, we need to consider the principle of conservation of momentum. According to this principle, the total momentum of an isolated system remains constant if no external forces act on it.
The momentum of an object is given by the formula:
Momentum = Mass × Velocity
For trolley X:
Mass = m
Velocity = Average speed of trolley X = 0.2 m/s
Momentum of trolley X = m × 0.2 m/s = 0.2m kg·m/s
For trolley Y:
Mass = 1/2m
Velocity = Average speed of trolley Y = 0.4 m/s
Momentum of trolley Y = (1/2m) × 0.4 m/s = 0.2m kg·m/s
Since the two trolleys are an isolated system and no external forces act on them, the total momentum after the release of the spring is the sum of the individual momenta:
Total momentum = Momentum of trolley X + Momentum of trolley Y
Total momentum = 0.2m kg·m/s + 0.2m kg·m/s
Total momentum = 0.4m kg·m/s
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