Answer:
b. at the top
Explanation:
At the top of the climb, the vertical velocity of Jeff's throw has a value of zero.
Vertical velocity in this instance is acting against the acceleration due to gravity.
At the top of the thrown, the force of the throw becomes zero and the velocity also becomes zero. As the body finds it way downward, it begins to fall freely. The fall is due to the acceleration due to gravity which is experienced by every object on earth.What Kinetic energy is exactly equal to Gravitational Potential Energy why is height halfway between the maximum height?
Explanation:
Let us calculate the work done in lifting an object of mass m through a height h, such as in Figure 1. If the object is lifted straight up at constant speed, then the force needed to lift it is equal to its weight mg. The work done on the mass is then W = Fd = mgh. We define this to be the gravitational potential energy (PEg) put into (or gained by) the object-Earth system. This energy is associated with the state of separation between two objects that attract each other by the gravitational force
Potential energy is a property of a system rather than of a single object—due to its physical position. An object’s gravitational potential is due to its position relative to the surroundings within the Earth-object system. The force applied to the object is an external force, from outside the system. When it does positive work it increases the gravitational potential energy of the system. Because gravitational potential energy depends on relative position, we need a reference level at which to set the potential energy equal to 0. We usually choose this point to be Earth’s surface, but this point is arbitrary; what is important is the difference in gravitational potential energy, because this difference is what relates to the work done. The difference in gravitational potential energy of an object (in the Earth-object system) between two rungs of a ladder will be the same for the first two rungs as for the last two rungs.
The diagram below shows the muzzle of a cannon located 50. meters above the ground. When the cannon is fired, a ball leaves the muzzle with an initial horizontal speed of 250. meters per second. [Neglect air resistance.]Which action would most likely increase the time of flight of a ball fired by the cannon?
Answer:positioning the cannon higher above the ground
Explanation:
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Please help me answer this i really need help!!!
How many times greater is the intensity of a 35-db sound compared to a 25-db sound?
Answer:
10 Times (greater)
Explanation:
The given parameters are;
The number of decibels of the first sound, 35-db
The number of decibels of the second sound, 25 db
We have;
[tex]\beta (dB) = 10 \cdot log_{10} \left (\dfrac{I}{I_0 \right)}[/tex]
Where;
I₀ = 10⁻¹² W/m² = The lowest perceivable sound
Therefore, we have;
[tex]I = I_0 \times 10^{\left (\dfrac{\beta }{10} \right) }[/tex]
Substituting the known values, gives;
When β = 35-db, we get;
[tex]I_{35} = 10^{-12} \times 10^{\left (\dfrac{35 }{10} \right) } = 10^{-12} \times 10^{3.5} = 10^{-8.5}[/tex]
When β = 25-db, we get;
[tex]I_{25} = 10^{-12} \times 10^{\left (\dfrac{25 }{10} \right) } = 10^{-12} \times 10^{2.5} = 10^{-9.5}[/tex]
Therefore, we get the number of times the intensity of a 35-db sound is compared to a 25-db sound, which is, I₃₅/I₂₅ is given as follows;
[tex]\dfrac{I_{35}}{I_{25}} = \dfrac{10^{-8.5}}{10^{-9.5}} = 10[/tex]
Therefore, the intensity of a 35-db sound is 10 times greater than the intensity of a 25-db sound
A plane is traveling at a velocity of 90 m/s. It accelerates at a constant rate of 1.5 m/s2 until its velocity reaches 500 m/s. What distance did the plane cover while it was accelerating?
Recall that
v ² - v₀² = 2 a ∆x
where
v₀ = initial velocity
v = final velocity
a = acceleration
∆x = distance
Then
(500 m/s)² - (90 m/s)² = 2 (1.5 m/s²) ∆x
∆x = ((500 m/s)² - (90 m/s)²) / (2 (1.5 m/s²))
∆x ≈ 80,633 m
Hydrogen sulfide, H2S, and hydrogen chloride, HCl, are both gases at temperatures above –50 °C.
Which gas will diffuse most rapidly at the temperature given?
A hydrogen chloride at –40°C
B hydrogen chloride at –20°C
C hydrogen sulfide at –40°C
D hydrogen sulfide at –20°C
could someone please explain this
Explanation:
A gas at higher temperature is able to gain more heat from the environment/surroundings and has more kinetic energy to diffuse at a faster rate.
Hence a temperature at -20°C is more ideal.
Molar mass of H2S = 34.07g/mol
Molar mass of HCl = 36.45g/mol
Since H2S has a smaller molar mass, the same number of moles of H2S gas will diffuse faster as compared to the same number of moles of HCl gas.
Hence the answer is Hydrogen sulfide at -20°C. (D)
Explain how we perceive objects as they are
pls help, I will mark u as the brainliest
The lens present in our eyes forms a real and inverted image on the retina. The optic nerves carry this image from the retina to the brain. The brain then processes this info to generate clear and virtual images. That's how we perceive objects as they are.
When the image is formed on our "Retina", the light sensitive cells of our Retina gets activated and they generate electric signals. These signals are send to brain by the optic nerves. The brain interprets the electric signals in such a way that we see an image in erect and of the same size as the object... MÅRK ÅS THE ẞRÅÏÑLÏËST.......
Pls help me with this problem!!
Answer:
v = 19.6 m/s.
Explanation:
Given that,
The radius of the circle, r = 5 m
The time period of the ball, T = 1.6s
We need to find the ball's tangential velocity.
The formula for the tangential velocity is given by :
[tex]v=\dfrac{2\pi r}{T}[/tex]
Putting all the values in the above formula
[tex]v=\dfrac{2\pi \times 5}{1.6}\\\\v=19.6\ m/s[/tex]
So, the tangential velocity of the ball is 19.6 m/s. Hence, the correct option is (c).
A plane's average speed between two cities is 750 km/hr. If the trip takes
2.5 hrs. how far does the plane fly?
Answer:
The plane goes for 600 km per hour.
The trip from a city to another is 2.5 hours
Basically, all you have to do is multiply 600 by 2.5.
That’s 1,500 kilometres.
Explanation:
A plane's average speed between two cities is 750 km/hr and if the trip takes 2.5 hours then the total distance covered by the plane would be 1875 kilometers.
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object.
As given in the problem, a plane's average speed between two cities is 750 km/hr and if the trip takes 2.5 hours then we have to find out the total distance covered by the plane,
The plane's average speed between two cities is 750 kilometers/hour,
time is taken in the whole trip = 2.5 hours
The distance covered by the plane = 750 kilometers/hour×2.5 hours
= 1875 kilometers
Thus, the total distance covered by the plane would be 1875 kilometers.
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6. A hockey player skates ten meters to the goal.
What term is used to describe the hockey
player's process of changing position?
Answer:
Displacement
Explanation:
Displacement is a term used to represent change in position.
Margaret Mary, Doug , and Kako are at a local amusement park. They see an attraction called the Giant Slide, which is simply a very long and high inclined plane. Visitors at the amusement park climb a long flight of stairs to the top of the 27inclined plane and are given canvas sacks. They sit on the sacks and slide down the plane 70m long. At the time when the three friends walked past the slide, a 135-kg man and a 20-kg boy are each at the top preparing to slide down. "I wonder how much less time it will take the man to slide down than it will take the boy," said Margaret Mary. "I think the boy will take less time," said Doug. "You're both wrong,"said Kako. "They will reach the bottom at the same time."
The question is incomplete. The compete question is :
Margaret Mary, Doug , and Kako are at a local amusement park. They see an attraction called the Giant Slide, which is simply a very long and high inclined plane. Visitors at the amusement park climb a long flight of stairs to the top of the 27inclined plane and are given canvas sacks. They sit on the sacks and slide down the plane 70m long. At the time when the three friends walked past the slide, a 135-kg man and a 20-kg boy are each at the top preparing to slide down. "I wonder how much less time it will take the man to slide down than it will take the boy," said Margaret Mary. "I think the boy will take less time," said Doug. "You're both wrong,"said Kako. "They will reach the bottom at the same time."
If the man and the boy do not take the same amount of time to reach the bottom of the slide, calculate how many seconds of difference there will between the two times.
Solution :
From body sliding down an incline plane, the acceleration is given by, [tex]$a = g \sin \theta$[/tex]
Since the body slides from rest, the initial velocity is, u = 0
Now the equation of motion, we have
v= u + at
or v = 0 +at
or v = at
or [tex]$t=\frac{v}{a}$[/tex] ............(1)
again we have, [tex]$v^2 -u^2 =2as $[/tex]
or [tex]$v = \sqrt{2s g \sin \theta} $[/tex]
Then from equation (1), we have
[tex]$t=\frac{\sqrt{2sg \sin \theta}}{g \sin \theta}$[/tex]
Thus this means that the time of sliding down an inclined plane does not depend on the mass of the body that slides.
Therefore, Kako is correct.
Since the time taken to slide an inclined plane is same for both the man and the boy, there is no difference between their time of sliding.
A car that travels at a velocity of 20 m/s and
has a mass of 1,200 kg.
Answer:
24000kgm/s
Explanation:
Given parameters:
Velocity = 20m/s
mass = 1200kg
Unknown:
Momentum = ?
Solution:
Momentum is the quantity of motion a body possesses.
This is given as:
Momentum = mass x velocity
Momentum = 1200 x 20 = 24000kgm/s
Nina's measurements, shown in the table here, BEST represent a wave with
A)
decreasing frequency.
B)
increasing frequency.
C)
increasing amplitude.
D)
decreasing amplitude.
Nina's data in this table most accurately depict a wave with decreasing frequency. Option A is right.
What is frequency?A recurring event's frequency is measured by how many times it occurs in a unit of time.
To emphasize distinctions with spatial and angular frequencies, respectively, it is also sometimes referred to as ordinary frequency or temporal frequency.
If the duration, or time interval, required to complete one cycle or vibration is half a second, the frequency is 2 per second; if it is one hundredth of an hour, the frequency is 100 per hour.
The frequency and period, or time interval, are often reciprocally equal, therefore frequency = 1/period = 1 in most circumstances.
The Moon rotates about Earth about a little bit more than 12 times a year. In a violin A string vibrates at a frequency of 440 cycles per second.
Thus, the correct option is A.
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As a pendulum moves closer to the equilibrium position, how do the velocity, acceleration, and force change? The velocity decreases, the acceleration decreases, and the net force decreases. The velocity increases, the acceleration decreases, and the net force decreases. The velocity increases, the acceleration increases, and the net force decreases. The velocity decreases, the acceleration increases, and the net force increases.
Answer:
The velocity increases, the acceleration decreases, and the net force decreases.
Explanation:
Velocity is at maximum when acceleration is zero thus as the pendulum moves closer to equilibrium position, velocity increases and acceleration decreases. As the pendulum moves closer to equilibrium, the magnitude of force decreases until it reaches the equilibrium position when the magnitude of force is zero. This means the net force decreases in the same manner the acceleration decreases because from the formula of force which is the product of mass and acceleration.
Answer:
B
Explanation:
on edge
find not true when the water freezes...
Answer: i think its c
Explanation:
Answer:
a
Explanation:
A 2.0kg rock is thrown straight up into the air with a speed of 30m/s. Ignore air resistance. What is the net force acting on the rock?
Answer:
19.6N
Explanation:
Given parameters:
Mass of rock = 2kg
Speed = 30m/s
Unknown:
Net force on the rock = ?
Solution:
The net force acting on this rock is a function of the acceleration due to gravity acting upon it.
Net force = weight = mass x acceleration due to gravity
Net force = 2 x 9.8 = 19.6N downward
Jack and Jill decide to run a race. Jack weighs 90 kg and Jill weighs 50 kg. At the end of the race it was decided that Jack and Jill tied so they had the same speed. Which person had more momentum ?
Answer: Jack.
Explanation:
Momentum is defined as the quantity of motion.
For an object that has a mass M, and a velocity V, the momentum is written as:
P = M*V
For this problem, we know that Jack and Jill had the same speed (so they had the same velocity), let's say that this velocity is v.
Then the momentum of Jack will be:
P = 90kg*v
And the momentum of Jill will be:
P = 50kg*v
We can see that Jack will have a larger momentum, and this is because he has a larger mass than Jill, but the same velocity as her.
Explain why refraction takes place.
Please help explain in a simple way
Answer:
lCdfKFBWRblNLWFNJLBe
Explanation:
jk jk Refraction is an effect that occurs when a light wave, incident at an angle away from the normal, passes a boundary from one medium into another in which there is a change in velocity of the light
A 70.0 kg base runner moving at a speed of 4.0 m/s begins his slide into second base. The coefficient of friction between his clothes and Earth is 0.70. His slide lowers his speed to zero just as he reaches the base. How much mechanical energy is lost because of friction acting on the runner? A. 1100 J B. 560 J C. 140 J D. 0J 8. How far does the runner slide? F. 0.29 m G. 0.57 m H. 0.86 m J. 1.2 m
Answer:
B. 560 J
J. 1.2 m
Explanation:
v = Final velocity = 0
u = Initial velocity = 4 m/s
[tex]\mu[/tex] = Coefficient of friction = 0.7
m = Mass of runner = 70 kg
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
Kinetic energy is given by
[tex]K=\dfrac{1}{2}m(v^2-u^2)\\\Rightarrow K=\dfrac{1}{2}\times 70\times (0^2-4^2)\\\Rightarrow K=-560\ \text{J}[/tex]
The mechanical energy lost is 560 J
Acceleration is given by
[tex]a=-\mu g\\\Rightarrow a=-0.7\times 9.81\\\Rightarrow a=-6.867\ \text{m/s}^2[/tex]
From kinematic equations we get
[tex]v^2-u^2=2as\\\Rightarrow s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{0^2-4^2}{2\times -6.867}\\\Rightarrow s=1.165\approx 1.2\ \text{m}[/tex]
The runner slides for 1.2 m
a. The amount of mechanical energy that is lost because of friction acting on the runner is: B. 560 J
b. The distance the runner slide is equal to: J. 1.2 m
Given the following data:
Mass = 70.0 kgSpeed = 4.0 m/sCoefficient of friction = 0.70.Acceleration due to gravity, g = 9.8 [tex]m/s^2[/tex]
a. To determine the amount of mechanical energy that is lost because of friction acting on the runner, we would calculate the change in kinetic energy:
Mathematically, the change in kinetic energy is given by the formula:
[tex]\Delta K.E = \frac{1}{2} m(v-u)^2[/tex]
Substituting the parameters into the formula, we have;
[tex]\Delta K.E = \frac{1}{2} \times 70(4-0)^2\\\\\Delta K.E = 35(4)^2\\\\\Delta K.E = 35 \times 16\\\\\Delta K.E = 560\;Joules[/tex]
Mechanical energy = 560 Joules
b. To determine how far (distance) the runner slide:
First of all, we would find the runner's acceleration.
[tex]Acceleration = ug\\\\Acceleration = 0.70 \times 9.8[/tex]
Acceleration = 6.86 [tex]m/s^2[/tex]
For distance:
[tex]V^2 = U^2 + 2aS\\\\4^2 = 0^2 + 2(6.86)S\\\\16=13.72S\\\\S=\frac{16}{13.72}[/tex]
Distance, S = 1.2 meters.
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Jackson throws a football 30 meters at a speed of 15 m/s. How long was the football in the air before Laurence caught it for touchdown
Answer:
2s
Explanation:
Given parameters:
Distance = 30m
Speed = 15m/s
Unknown:
Time before Laurence caught it = ?
Solution:
To solve this problem;
Speed = [tex]\frac{disance }{time}[/tex]
Time taken = [tex]\frac{distance }{speed }[/tex] = [tex]\frac{30}{15}[/tex] = 2s
The time it takes is 2s
Given:
30 metersSpeed of 15 m/sWe will solve:
Speed = [tex]\frac{distance}{time}[/tex]
Time taken = [tex]\frac{distance}{time}[/tex] = [tex]\frac{30m}{15m/s}[/tex] = 2s
The time it takes is 2s
What is the molarity of 2 mol of calcium carbonate, CaCl2, dissolved in 1 L of solution?
HELP PLSS!!!!
Answer:
2mol/L
Explanation:
Given parameters:
Number of moles of calcium carbonate = 2mol
Volume of solution = 1L
Unknown:
Molarity = ?
Solution:
The molarity of a solution is the number of moles of solute dissolved or contained in a solution:
Molarity = [tex]\frac{number of moles }{volume }[/tex]
Molarity = [tex]\frac{2}{1}[/tex] = 2mol/L
an object has a mass of 2,000kg. what is its weight on earth? show your work
Answer:
Answer: 19,600 N
Explanation:
Weight is a force, and force equals mass times acceleration. So the formula for weight is w = m • g
Every rock that you find must be or have at one time been a/an
Answer:
crystal
Explanation:
well most rocks are like that
a.) Determine the work done by Zach on the bull.
Explanation:
The unit of work done is in Joules
Work done is a physical quantity that is defined as the force applied to move a body through a particular distance.
Work is only done when the force applied moves a body through a distance.
Work done = Force x distance
The maximum work is done when the force is parallel to the distance direction.
The minimum work is done when the force is at an angle of 90° to the distance direction.
So to solve this problem;
multiply the force applied by Zack and distance through which the bull was pulled.
White Lake was contaminated with the Chemical Complany dispersing their waste in the lake. Eventually, they were forced to stop dumping it into the lake. using 2-3 sentences, please share what you know about this and if you think the lake is completely cleaned up.
Answer:
White Lake was contaminated with the Chemical Complany dispersing their waste in the lake. Eventually, they were forced to stop dumping it into the lake
What is different about parasitism compared to the other biological relationships such as mutualism, predation, competition, and commensalism?
Answer: parasitic organisms cause harm to other organisms.
Answer:
parasitic organisms cause harm to other organisms.
Explanation:
Suppose Alex is navigating using a compass. She starts walking at an angle of 60° north of east and walks a total of 100 m. How far north is she from the starting point? How far east?
Answer:
[tex]50\:\mathrm{m\: North}\\50\sqrt{3}\:\mathrm{m\: East}[/tex]
Explanation:
We can create a 30-60-90 triangle. The distance she walked is then the hypotenuse of the triangle, and using 30-60-90 triangle rules, we have the following:
The North leg is opposite to the [tex]30^{\circ}[/tex] angle. Therefore, if we call this distance [tex]y_N[/tex], we have the following:
[tex]\sin 30^{\circ}=\frac{y_N}{100},\\\frac{1}{2}=\frac{y_N}{100},\\y_N=\fbox{$50\:\mathrm{m}$}[/tex].
The East leg is opposite to the [tex]60^{\circ}\\[/tex] angle. If we call this distance [tex]x_E[/tex], we have:
[tex]\sin 60^{\circ}=\frac{x_E}{100},\\\frac{\sqrt{3}}{2}=\frac{x_E}{100},\\x_E=\fbox{$50\sqrt{3}\:\mathrm{m}$}[/tex].
Two charged objects are held 1 meter apart from each other. Then they are moved to 2
meters apart. How is the electrostatic force and gravity force between
them affected by this move?
O
A Gravity will be as strong and the electrostatic force will be strong.
O
B. Both forces will be as strong after the move,
C. Gravity will be as strong and the electrostatic force will be as strong.
OD. Both forces will be as strong after the move.
Answer:
c
Explanation:
mark ma es brainliest
When two charged objects are moved to 2 meters apart from 1 meter. Then, both Gravity and electrostatic forces will be weak.
The electrostatic force and gravity force is inversely proportional to square of distance between two objects.
[tex]F\alpha\frac{1}{r^{2} }[/tex]
Where r is distance between both charged objects.
When two charged objects are moved to 2 meters apart from 1 meter. Then, both Gravity and electrostatic forces will be weak.
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what happens if I increase the height of a skater
Answer:
The higher the skater is the more potential energy he has. As his height decreases, his potential energy decreases and his kinetic energy increases.
Explanation:
Make me BRAINLIST please
Answer:
The higher the skater is the more potential energy he has. As his height decreases, his potential energy decreases, and his kinetic energy increases. ... Explore how the skater's change in speed relates to the potential and kinetic energy of the skater.
Explanation:
(Via Uteach)
in which diagram 1 or 2 would the person be experiencing summer? explain
Answer:
Diagram 1
Explanation:
In diagram one, the earth is leaning toward the sun, meaning it is summertime.
The person will experience summer in diagram one because the earth is tilted towards the sun.
What is the summer season?From diagram one we can see that earth is tilted towards the sun. During summer, the North Pole of the earth is tilted towards the sun.
As a consequence, the sun’s path is higher in the sky, causing the northern hemisphere to receive more light and heat.
In addition, because the sun is in the sky for more hours, the summer solstice is also the longest day of the year.
These extra hours of sunlight give the sun more time to heat the earth and this is the main reason for summer to be the hottest season.
During summer the sun is perpendicular to the tropic of cancer and heats more areas that lie in the tropic of cancer.
Thus the answer will be diagram 1 because the earth is tilted towards the sun.
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