Question

If an object of mass 2 kg is thrown up from the ground reaches a height of 5 m and falls back to the
Earth (neglect the air resistance). Calculate
(1) The work done by gravity when the object reaches 5 m height.
(11) The work done by gravity when the object comes back to Earth.
(u) Total work done by gravity both in upward and downward motion and mention the physical
significance of the result.

Answer 1

Answer:

Explanation:

Mass,m=2 kg

height, h=5m

(1)Here, displacement is 5m

  Therefore, wok done=mgh

                                     =2*9.8*5

                                     =98J

(Specifically, -98J since force and displacement are in opposite direction)

(2)displacement=5m again

Hence, work done=98J, now +98J,since force and displacement in same direction.

(3)Total work done=Zero