All Exams Test series for 1 year @ ₹349 only
Question

When a ball rolls down a hill and comes to rest, how is the total energy of the ball-earth system maintained?

The correct answer is

The initial potential energy becomes heat and sound energy

By the law of conservation of energy, energy can neither be created nor destroyed; it only changes from one form to another, so the total energy of the ball-earth system stays constant.

At the top of the hill the ball has potential energy. As it rolls down, this potential energy changes into kinetic energy. Friction between the ball and the ground and air resistance then convert the kinetic energy into heat (thermal energy) and sound, and when the ball stops, the energy lost from its height has appeared as heat and sound.

Energy is not destroyed when the ball stops. It cannot all remain as potential energy because the ball is now lower down, and it cannot all remain as kinetic energy because a ball at rest has zero kinetic energy.

Hence, The initial potential energy becomes heat and sound energy.

Was this answer helpful?

Similar Questions

  1. When a ball falls freely from a height, what happens to its potential and kinetic energy according to the law of conservation of energy?

  2. An electric motor is rated at 250 W. In a physics experiment, it is used to lift a load performing 7500 J of work. What does the rating indicate in this context?

  3. Which of these examples best illustrates that work is not done according to physics?

  4. An object is moving with uniform velocity, and a force acts in the opposite direction to stop it. What is the sign of the work done by this force?

  5. A block moving on a horizontal surface experiences a force of friction of 15 N in the opposite direction. If the displacement of the block is 5 m, how much work is done by the force of friction?

  6. In a solar-powered calculator, which sequence best represents the conversion of energy forms from sunlight to calculation display?

  7. Which of the following quantities is needed to calculate the work done by a constant force?

  8. What will be the power delivered by a lamp that uses 120 joules of energy in 2 minutes?

  9. How does the direction of the applied force relative to the object's motion affect the amount of work done?

  10. In which scenario does an object have zero gravitational potential energy with respect to a given reference point?


Important Questions from Work Power Energy

  1. Which of the following is NOT correct regarding friction?

  2. If a pump can raise 200 liters of water through a height of 300 meters in one minute, how much work can it do in one hour?

  3. Which of the following is an example of kinetic energy?

  4. How much kinetic energy does a 160 g cricket ball have when it is thrown at a speed of 22 m/s?

  5. The movement of birds is an example of _______.

Need Expert Advice?
Upcoming Exams
RRB JE
October 27, 2026
RRB ALP
November 03, 2026
Test Series
RRB Technicians img
Railways
RRB Technician Grade 1 (Signal) 2026 Mock Test Series
270 Tests 3 Tests Free
7598 Attempts
4.8(211)
English, Hindi, Bengali +7 More
More Questions from RRB Technicians

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App