Answer:
the power of the two light bulbs is 23.4 W
Explanation:
Given;
the resistance of the two identical light bulbs in series, R₁ and R₂ = 6.77 ohms and 6.77 ohms respectively
battery voltage , V = 17.8 V
The equivalent resistance of the two light bulbs, R = R₁ + R₂
R = 6.77 + 6.77
R = 13.54 ohms
The power of the two light bulbs is calculated as follows;
[tex]P = IV = (\frac{V}{R} )V = \frac{V^2}{R} = \frac{17.8^2}{13.54} = 23.4 \ W[/tex]
Therefore, the power of the two light bulbs is 23.4 W
A hoop is rotating at 12 rad/s on a horizontal plane about an a vertical axis that passes through its
edge when a second body with mass one quarter of the disc's is placed safely on it just opposite of the
pivot. What is the percentage change of the kinetic energy of the hoop?
A. 20%
B. 80%
C. 36%
D. 64%
Answer:
the correct answer is C
Explanation:
For this exercise we can use the conservation of angular momentum, let's define a system formed by the disk and the other body, so that the torques during the collision have been internal and the moment is conserved.
Initial instant. Before placing the second body
L₀ = I₁ w₁
Final moment. Right after placing the body
L_f = (I₁ + I₂) w
the moment of inertia of the ring with respect to an axis passing through its center is tabulated
I_{cm} = m r²
we use the parallel axes theorem to find the moment of inertia about an axis passing through one end
I₁ = I_{cm} + m d²
where d is the distance from the center of mass to the new axis
d = r / 2
we substitute
I₁ = mr² + m (r/2)²
I₁ = 5/4 m r²
The second body does not specify a specific shape, so we can assume it to be punctual
I₂ = m’ (2r)²
I₂ = 4 m’ r²
in the exercise indicate that
m ’= m / 4
I₂ = m r²
how the moment of inertia is conserved
L₀ = L_f
I₁ w₁ = (I₁ + I₂) w
5/4 m r² w₁ = (5/4 m r² + m r²) w
5/4 m r² w₁ =9/4 m r² w
w = 5/9 w₁
we calculate
w = 5/9 12
w = 6.67 rad / s
having the initial and final angular velocities we can find the kinetic energy of the hoop
K₀ = ½ I₁ w₁²
K_f = ½ (I₁) w2
the energy ratio is
[tex]\frac{K_f}{K_o}[/tex] = [tex]\frac{w^2}{w_1^2}[/tex]
\frac{K_f}{K_o} = (6.67 / 12)²
\frac{K_f}{K_o} = 0.309
[tex]\frac{K_f}{K_o} %[/tex] = 31%
the correct answer is C
When scientists use one of their five senses to gather information, they are
A.
drawing a conclusion.
B.
making an inference.
C.
predicting a relationship
D.
making an observation.
Answer:
making an observation
Explanation:
A farmer plants the same crop in a field year after year. Every year there are months during which the field is left without any plants. The farmer notices a decline in soil
quality during these months. What causes this decrease in soil quality?
Erosion
Drought
Desertification
Consumption of nutrients by the crops
Answer:
Drought
Explanation:
how did each scientist contributed to cell theory?
Contribution to cell theory:
Robert Hooke
Anton Leeuwenhoek
Matthias Schleidan
Theodor Schwann
Answer:
Matthias Schleidan
Explanation:
because Matthias Schleiden found that all plants are composed of cells, and communicated the finding to Schwann, who had found similar structures in the cells. Other researchers confirmed the similarity, as explained in his book, where he concluded, "All living things are composed of cells and cell products.
This became the cell theory.
I learn that in my old school.
A graduated beaker with 375 mL of water is sitting on a scale which measures the weight of the glass and water to be 7.60 N. When a rock is put into the glass, the volume level of the water changes to 450 mL and the scale reading changes to 9.22 N. What is the specific gravity of the rock
Answer:
Volume of water displaced = 450 - 375 = 75 ml
Vr = volume of rock = 75 ml
Wr = 9.22 - 7.60 = 1.62 N weight of 75 ml of rock
Density of rock = 1.62 N / 75 ml = .0216 N / ml
Density of water = 1000 g / 1000 ml = 9.8 N / 1000 ml = .0098 N / ml
Density of rock / density of water = .0216 / .0098 = 2.20
The specific gravity of the rock in the given water volume is 0.2.
The given parameters;
initial volume of the water, = 375 mlweight of the water, = 7.6 Nfinal volume of water = 450 mlchange in scale reading = 9.22 NThe specific gravity of the rock is calculated as follows;
[tex]S.G = \frac{weight \ in \ air}{Weight \ in \ water} \\\\S.G = \frac{450 - 375}{375} \\\\S.G = 0.2[/tex]
Thus, the specific gravity of the rock in the given water volume is 0.2.
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1. If airbags reduce the impact force from an accident why has there been questions over their safety?
2. Are airbags the safest option to prevent serious injury or death from a car accident?
Answer:Air bags can leave you in even more injury, From the impact they give
You could end up with a broken nose,arm
concussion
Which of the following is an
example of thermal energy?
A. turning on a lamp so you can read
B. rubbing your hands together to get warm
C. kicking a ball
three small balls each of mass 13.3g are suspended separately from a common point by silk threads, each 1.17m long. The balls are identically charged hang at the corners of equilateral triangle 15.3 cm on a side. Find the charge on each ball
The charge on each ball is 6.1 ×10⁻⁸ C.
What is force?The definition of force in physics is: The push or pull on a massed object changes its velocity.
An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude. A spring balance can be used to calculate the Force. The Newton is the SI unit of force. Force is a vector quantity and it has both magnitude and direction.
Let the balls have equal charge of q. Then, electrostatic force acting on each particle = √3 q²/r² dyne = √3 q²/15² dyne =0.0076 q².
Weight of each ball = 13.3 ×980 dyne = 13034 dyne.
As the electrostatic force and the weight acts perpendicular to each other.
Hence, 0.1/√3 = 0.0076 q²/13034
q = 6.1 ×10⁻⁸ C
Hence, the charge on each ball is 6.1 ×10⁻⁸ C.
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Consult Multiple-Concept Example 5 to review the concepts on which this problem depends. A light bulb emits light uniformly in all directions. The average emitted power is 150.0 W. At a distance of 6 m from the bulb, determine (a) the average intensity of the light, (b) the rms value of the electric field, and (c) the peak value of the electric field.
Answer:
a. 0.332 W/m² b. 11.2 V/m c. 15.8 V/m
Explanation:
(a) the average intensity of the light,
Intensity, I = P/A where P = average power = 150.0 W and A = area through which the power emits = 4πr² where r = distance from bulb = 6 m.
So, I = P/A = P/4πr²
Substituting the values of the variables into the equation, we have
I = P/4πr²
I = 150.0 W/4π(6 m)²
I = 150.0 W/4π(36 m²)
I = 150.0 W/452.39 m²
I = 0.332 W/m²
(b) the rms value of the electric field,
Since Intensity, I = E²/cμ₀ where E = rms value of electric field, c = speed of light = 3 × 10⁸ m/s and μ₀ = permeability of free space = 4π × 10⁻⁷ H/m.
Making E subject of the formula, we have
E² = Icμ₀
E = √(Icμ₀)
Since I = 0.332 W/m², substituting the other terms into the equation, we have
E = √(0.332 W/m² × 3 × 10⁸ m/s × 4π × 10⁻⁷ H/m.)
E = √(0.332 W/m² × 3 × 10⁸ m/s × 4π × 10⁻⁷ H/m.)
E = √(12.5 × 10)
E = √125 V/m
E = 11.18 V/m
E ≅ 11.2 V/m
(c) the peak value of the electric field.
The peak value of electric field, E' is gotten from E = E'/√2 where E = rms value of electric field.
So, E' = √2E
= √2 × 11.2 V/m
= 15.81 V/m
≅ 15.8 V/m
A mountain climber, in the process of crossing between two cliffs by a rope, pauses to rest. She weighs 520 N. As the drawing shows, she is closer to the left cliff than to the right cliff, with the result that the tensions in the left and right sides of the rope are not the same. Find the tensions in the rope to the left and to the right of the mountain climber.
Answer:
The answer is "892.90 N"
Explanation:
Following are the solution to these question:
Calculating the vertical force of the summation that is equal to zero:
[tex]\to TL \cos 65 + TR \cos 80 -520 = 0\\\\\to 0.4226\ TL + 0.1736\ TR = 520\\[/tex]
Calculating the sum of horizontal forces that is equal to zero:
[tex]\to TL\sin 65 - TR \sin 80 = 0 \\\\\to 0.9063TL - 0.9846TR = 0\\\\\to TL = (\frac{0.9846}{0.9063})\ TR \ \ = 1.0866\ TR\\\\\to 0.4226(1.0866) \ TR +0.1736\ TR =520 \ N\\\\\to 0.6328 \ TR = 520 \\\\\to TR = 821.74 \ N \\\\\to TL = 1.0866 \times 821.74 = 892.90\ N[/tex]
If an object is placed between the focal point and twice the focal length of a convex lens, which type of image will be produced?
A.
real, upright, and magnified
B.
virtual, inverted, and smaller
C.
virtual, upright, and magnified
D.
real, inverted, and magnified
E.
real, upright, and smaller
Answer: I think its D
Explanation: Hope this was helpful...
How does increasing the number of resistors in a parallel branch change the total resistance of the system?
Increasing the number of resistors in a parallel branch, decreases the total resistance of the system.
What is parallel branch?Parallel resistive circuit is one where the resistors are connected to the same two points (or nodes) and is identified by the fact that it has more than one current path connected to a common voltage source.
As more and more resistors are added in parallel to a circuit, the equivalent resistance of the circuit decreases and the total current of the circuit increases.
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A quasar is a distant celestial body in space. Investigators use a special telescope and determine that a certain quasar was giving off waves with a frequency of 1.41 X 109 Hz. An electromagnetic spectrum is shown above. The investigators were most likely using a telescope that detects which type of wave?
Answer:
equipment for the measurement of microwave L bands with a range between 1 GHz and 2 GHz.
Explanation:
The electromagnetic spectrum can be calculated with the relationship between the speed of light, its wavelength and its frequency.
c = λ f
For reasons of analysis and equipment used, it is artificially divided into ranges, with poorly defined limits and in some cases with overlaps between some.
For the case of analysis, f = 1.41 10⁹ Hz, we have the range called
* Microwave for f> 3 108 Hz to approximately f <3 1011 Hz
For the lower part of the frequency 3 10⁸ <f <3 10⁹ Hz we have UHF television channels and cell phones and military communications.
As the frequency observed by the researchers is in the UHF range, it is possible that they are using microwave equipment for communications, specifically equipment for the measurement of microwave L bands with a range between 1 GHz and 2 GHz.
Three resistors: R1 = 5 Ω,R2 = 3 Ω, and R3 = 4 Ω are connected in series to each other. A voltmeter connected in parallel to resistor R2 measures voltage of 6 V. What is the current through the battery?
Answer: current I= 2 A
Explanation: when resistors are in series current I is same
Through each resistor. Potential drop along resistor R is
ΔV= IR. then I = ΔV/R = 6V/3Ω
Three resistors: R1 = 5 Ω,R2 = 3 Ω, and R3 = 4 Ω are connected in series to each other. A voltmeter connected in parallel to resistor R2 measures a voltage of 6 Volts, then the current flowing through the battery would be 2 Ampere.
What is resistance?Resistance is the obstruction of electrons in an electrically conducting material.
As given in the problem ,Three resistors: R1 = 5 Ω,R2 = 3 Ω, and R3 = 4 Ω are connected in series to each other. A voltmeter connected in parallel to resistor R2 measures a voltage of 6 V.
By using Ohm's Law,
V = IR
6 Volt = Electric current × 3 Ohms
Electric current = 6 volt / 3 Ohm's
= 2 Ampere
Thus, the current flowing through the battery would be 2 Ampere.
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Cathode ray tubes (CRTs) used in old-style televisions have been replaced by modern LCD and LED screens. Part of the CRT included a set of accelerating plates separated by a distance of about 1.40 cm. If the potential difference across the plates was 23.0 kV, find the magnitude of the electric field (in V/m) in the region between the plates.
Answer:
E = 1.64 x 10⁶ V/m
Explanation:
The electric field in the region between the plates can be given by the following formula:
[tex]E = \frac{\Delta V}{d}[/tex]
where,
E = Electric Field = ?
ΔV = Poetential Difference across the plates = 23 KV = 23000 V
d = distance between plates = 1.4 cm = 0.014 m
Therefore, using these values in the equation, we get:
[tex]E = \frac{23000\ V}{0.014\ m}[/tex]
E = 1.64 x 10⁶ V/m
What determines how powerful a magnet is?
Answer:
I would assume a force of gravitational pull.
Explanation:
Answer: How powerful the pull is or how many magnetic things it can pick up at one time, or a heavy magnetic object.
Explanation:
Surface tension is often calculated using a machine that lifts a wire ring from the surface of a liquid. In this case the ring and liquid have some cohesive forces and attract rather than repel. In order to lift a ring of radius 2.75 cm off of the surface of a pool of blood plasma, a vertical force of 2.00*10-2 N greater than the weight of the ring is required. Consider the situation just before the ring breaks contact with the blood plasma where the blood plasma makes a contact angle of approximately zero degrees along the circumference of the ring and is stretched down vertically on both sides of the ring.
Required:
Calculate the surface tension of blood plasma from this information.
Answer:
0.116 N/m
Explanation:
Since the net force acting on the ring must be greater than 2.00 × 10⁻² N, and the surface tension T = F/L where F = net force = 2.00 × 10⁻² N and L = circumference of ring = 2πr where r = radius of ring = 2.75 cm = 2.75 × 10⁻² m.
So, T = F/L
= F/2πr
= 2.00 × 10⁻² N ÷ 2π(2.75 × 10⁻² m)
= 1/2.75π N/m
= 1/8.64 N/m
= 0.116 N/m
I need a response quick
6. A car is traveling from 0-20 m/s in :05 seconds. What is the acceleration?
7. A roller coaster travels from 0-40 m/s in :08 seconds. What is the acceleration?
Answer: mark me branliest plz
Explanation:
Two objects with masses 5. 4 meters per second in 20. 8 m/s? At the end of ... A -kilogram car travels at a constant speed of 20. 18 m/s . 8 m/s2). The acceleration due to ... 5 seconds. the maximum speed an object can travel falling towards earth. ... 1 (4) 7. 0 3 101 m 3. 19)An object is dropped and falls freely to the ground ...
HELP ASAP GIVING 5 PTS AND BRAINLIEST
Which of the following is an example of a constructive force that helps to shape Earth's land?
A. When two plates in the Earth's lithosphere collide and cause the land to rise up into a mountain
B. When glaciers break pieces of a mountain away as they slide downward
C. When erosion, due to rain, wind, snow, and ice, wears away a mountain top
The answer is C I believe
A bus is moving at a speed of 150km/hr. Begins to slow at a constant rate of 3.0m/s each second. Find how far it goes before stopping
Answer:
Distance = 13.9 meters
Explanation:
Given the following data;
Maximum speed = 150 km/hr to meters per seconds = 150 * 1000/3600 = 41.67 m/s
Decelerating speed = 3m/s
To find the distance travelled with this speed;
Distance = maximum speed/decelerating speed
Distance = 41.67/3
Distance = 13.9 meters
Therefore, the bus would travel a distance of 13.9 meters before stopping.
2.3 The motion of an object is accelerated
when its speed:
a
decreases
b remains constant
increases.
Answer:
The motion of an object is accelerated when its speed increases.
You are a member of an alpine rescue team and must get a box of supplies, with mass 3 kg , up an incline of constant slope angle 30.0, so that it reaches a stranded skier who is a vertical distance 4 m above the bottom of the incline. There is some friction present; the kinetic coefficient of friction is 0.05. Since you can't walk up the incline, you give the box a push that gives it an initial velocity; then the box slides up the incline, slowing down under the forces of friction and gravity. Take acceleration due to gravity to be 9.81 m/s2 .What is the minimum speed v that you must give the box at the bottom of the incline so that it will reach the skier
Answer:
v = 9.04 m / s
Explanation:
For this exercise we can use the relation that the work of the non-conservative force (friction) is equal to the variation of the mechanical energy of the system.
W = Em_f - Em₀ (1)
Starting point. Lower slope
Em₀ = K = ½ m v²
highest point. Where is the skier at a height h
Em_f = U = m g h
The work of rubbing
W = -fr x
the negative sign is because the friction force opposes the movement.
Let's set a reference system where the x axis is parallel to the slope and the y axis is perpendicular
let's use trigonometry to break down the weight
cos θ = W_y / W
sin θ = Wₓ / W
W_y = W cos θ
Wₓ = W sin θ
Y axis
N - Wₓ = 0
N = mg sin θ
X axis
fr = m a
the friction force has the expression
fr = μ N
fr = μ mg sin θ
we look for the job
W = - μ mg sin θ x
where x is the distance along the slope
we substitute in 1
-μ mg sin θ x = mg h - ½ m v²
let's use trigonometry to find the distance x
tan 30 = h / x
x = h / tan 30
we substitute
- [tex]\mu \ mg \ sin \theta \ \frac{h}{tan 30} \ x[/tex] = m gh - ½ m v²
we use
tan 30 = sin30 / cos30
v² = 2g h + 2 μ g h cos 30
v = [tex]\sqrt{ 2gh \ (1+ cos 30}[/tex]
let's calculate
v = [tex]\sqrt{ 2 \ 9.8 \ 4 \ (1 + 0.05 \ cos \ 30)}[/tex]
v = 9.04 m / s
Need help on question one ASAP pls help
Answer:
B
Explanation:
Because blocks 2 and 3 have sides with unequal forces while block 1 doesnt. Plz drop a follow if this helps! ❤
26. Which member of the carbon family is a non-metal?
Please help
Explanation:
Check out the Periodic Table attached here. The Carbon family is the vertical group starting with Carbon, Group 14. Nonmetals are in green, which element there is a nonmetal?
I need help please .
Answer:
option 5
Explanation:
because all u do is have to add them up
Please help !!!!!!!!!!!!!!!
Answer:
9v
Explanation:
the equation P^xV^yT^z= constant is Boyle law for what is the values of x,y,z
I learned the equation as P•V=k•T .
So x=1, y=1, and z= -1 .
What kind of weather would MOST LIKELY lead to hurricane formation?
Answer:
The recipe for a hurricane is a combination of warm, humid wind over tropical waters. The temperature of tropical waters must be at least 80 degrees F for up to 165 feet below the ocean’s surface. As this warm water meets the wind that blows west from Africa across the ocean, it causes the water to vaporize. The water vapor then rises into the atmosphere, where it cools and liquefies.
Explanation:
I hope this helps
please someone help me !!
Answer:
D
Explanation:
because if the solvent is more than the solvent then we can't resolve it.
so our product will be suspended
how many states a water has
three different states
Water is known to exist in three different states; as a solid, liquid or gas. Clouds, snow, and rain are all made of up of some form of water. A cloud is comprised of tiny water droplets and/or ice crystals, a snowflake is an aggregate of many ice crystals, and rain is just liquid water.
Answer:
liquid water gas water vapour solid ice