The work done by the gravitational force on an object as it moves from a reference level to a higher point is:
- A. Always positive
- B. Always negative
- C. Zero
- D. Depends on the path taken
Explanation
Gravity acts downwards while the displacement is upwards, so the force has a component opposite to the motion and the work it does is negative, which is exactly why the potential energy of the object increases. Coming back down, gravity does positive work. Because gravity is a conservative force, the work depends only on the change in height and not on the path.
Related questions
A ball is dropped from rest. Ignoring air resistance, as it falls its
The gravitational potential energy gained by a 2 kg mass lifted through 5 m, taking g as 10 m s-2, is
The gravitational potential energy gained by a body of mass m raised through a height h near the Earth's surface is
A body of mass 2 kg is raised 5 m. Taking g as 10 m per second squared, the potential energy gained is
A ball is dropped from a height h. Just before it hits the ground, its speed is