Work and Energy Worksheet-5
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Write an expression for the kinetic energy of a body of mass m moving with a velocity v.
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If the speed of a body is halved, what will be the change in its kinetic energy?
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On what factors does the kinetic energy of a body depend?
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Which would have a greater effect on the kinetic energy of an object : doubling the mass or doubling the velocity?
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How fast should a man of 50 kg run so that his kinetic energy be 625 J?
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State whether the following objects possess kinetic energy, potential energy, or both:
A man climbing a hill
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State whether the following objects possess kinetic energy, potential energy, or both:
A flying aero plane
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State whether the following objects possess kinetic energy, potential energy, or both:
A bird running on the ground
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State whether the following objects possess kinetic energy, potential energy, or both:
A ceiling fan in the off position
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State whether the following objects possess kinetic energy, potential energy, or both:
A stretched spring lying on the ground.
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Two bodies A and B of equal masses are kept at heights of h and 2h respectively. What will be the ratio of their potential energies?
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What is the kinetic energy of a body of mass 1 kg moving with a speed of 2 m/s?
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Is potential energy a vector or a scalar quantity?
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A load of 100 kg is pulled up by 5 m. Calculate the work done, (g = 9.8 m/s2)
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State whether the following statement is true or false :
The potential energy of a body of mass 1 kg kept at a height of 1 m is 1 J.
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What happens to the potential energy of a body when its height is doubled?
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What kind of energy is possessed by the following?
A stone kept on roof-top.
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What kind of energy is possessed by the following?
A running car.
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What kind of energy is possessed by the following?
Water stored in the reservoir of a dam.
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What kind of energy is possessed by the following?
A compressed spring.
Answer:
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Kinetic energy = (1/2)mv2
Where m = mass of the body And v = velocity of the body (speed of the body)
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Becomes one-fourth
Kinetic energy = (1/2)mv2 If speed is halved KE will be one fourth.
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Mass and speed
Kinetic energy = (1/2)mv2
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Doubling the velocity
Since Kinetic energy = (1/2)mv2
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5 m/s
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Both kinetic energy and potential energy
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Both kinetic energy and potential energy
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Only kinetic energy
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Only potential energy
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Only potential energy (rather elastic potential energy)
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1:2
Using PE = mgh
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Using the formula
Kinetic energy = (1/2)mv2
2 J
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Scalar
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4900 J
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False
PE = mgh so value of g is to be put
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Potential energy gets doubled
PE = mgh so if height is doubled PE is also doubled.
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Potential energy
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Kinetic energy
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Potential energy
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Potential energy
