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CISCEICSE ICSE Class 8
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Syllabus

Energy - Mechanical Energy

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Topics

  • Introduction
  • Experiment

Introduction:

The energy used for doing mechanical work is called mechanical energy. Potential energy refers to stored energy, while kinetic energy refers to energy due to motion. 

  • Stretching and releasing the rubber of a catapult returns it to its original shape, causing the stone to shoot off. Similarly, a toy begins to move when you wind its spring and then release it.
  • When water stored at a height falls on a wheel, it makes the wheel turn. Each of these examples exhibits movement, indicating the completion of work.
  • There are two types of mechanical energy, namely, potential energy and kinetic energy. Position generates potential energy, while motion generates kinetic energy.
  • Potential energy is the energy stored in an object because of its position or state (like a stretched rubber band or water at a height).
  • Release of the object (like the rubber, spring, or water) converts the stored potential energy into kinetic energy, causing the object to move or perform work.

Potential energy

Experiment:

1. Aim: To observe how energy is transferred from one object to another and understand the difference between potential and kinetic energy.

2. Requirements: two balls (marbles or any small balls) and a table.

3. Procedure

  • Step 1: Place one ball in a stable position at the centre of the table. This ball will not move initially.
  • Step 2: Place the second ball on the table and push it so that it moves towards the first ball.
  • Step 3: Observe what happens when the second ball hits the first ball. Notice that the first ball starts moving.

4. Observation: The second ball transfers its energy to the first ball, causing the first ball to move.

5. Conclusion

  • The second ball got its energy when it was pushed, and this energy is called kinetic energy, which is the energy an object has due to its motion.
  • The first ball was stationary and had potential energy due to its position, but once it was hit, it started moving, turning its potential energy into kinetic energy.

This experiment shows that mechanical energy consists of two types:

  • Potential energy (from the position of the object) and
  • Kinetic energy (from the motion of the object).

 Kinetic energy

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