2015 · Q50
An object is raised to a height of 3 m from the ground. It is then allowed to fall on to a table 1 m high from ground level. In this context, which one among the following statements is correct?
General KnowledgePhysics
- AIts potential energy decreases by two-thirds its original value of total energy.
- BIts potential energy decreases by one-third its original value of total energy.
- CIts kinetic energy increases by two-thirds, while potential energy increases by one-third.
- DIts kinetic energy increases by one-third, while potential energy decreases by one-third.
Explanation
The object's initial potential energy is mg×3. On the 1-m-high table it is mg×1, so the decrease is mg×2 — which is two-thirds of the original mg×3. Option A is correct; the lost potential energy appears as kinetic energy during the fall.