Question

what are the phsyics misconceptions that students normally encounter in 'work, energy and power'. especially when there is gain or loss in kinetic energy and potential energy

Answer 1

Common Physics misconceptions students normally encounter in ' work, energy and power'

1. Work done by a force depends on time : Work done by a force is independent of time taken. It depends only on force applied and displacement of object

2. If force is being applied, then work must be done: Work done by a force also depends on angle between force and displacement. If angle is 90 degrees then work done by force is zero

3. An object will have no energy if it is at rest: An object at rest may possess potential energy

4. If momentum of object is zero, then its energy is zero: An object with zero momentum will be at rest but may possess potential energy

5. Energy gets used up: Energy never get used up, it can only change its form.

6. During free fall total mechanical energy of object does not change. It remains constant. The amount of kinetic energy gained is equal to the amount of potential energy lost

7. Work done on an object by different force is equal to change in its mechanical energy: Work done = change in its kinetic energy only