Final answer:
Work is done on a leaf as it falls from a tree due to the force of gravity causing it to move. The kinetic energy and the change in gravitational potential energy observed would be the same for both observers regardless of their positions, but the final gravitational potential energy would differ based on their reference points.
Step-by-step explanation:
If a leaf falls from a tree, work has been done on the leaf by the force of gravity. Work, in physics, is defined as the process of a force causing an object to move. In this case, the force is gravity which pulls the leaf downward, and the leaf moves through a distance as it falls to the ground. Therefore, work is done on the leaf.
Considering the energy of the leaf observed by two people, one on a ladder and the other on the ground:
- (a) the kinetic energy of the leaf would be the same for both observers, as it only depends on the mass and the velocity of the leaf.
- (b) the change in gravitational potential energy would be the same since it depends on the leaf's mass, the height it falls through, and the acceleration due to gravity, none of which are influenced by the observers' positions.
- (c) the final gravitational potential energy would be different for the two individuals, assuming the person on the ground is considering the ground as the reference level and the person on the ladder considers the point at their height as the reference level.