Question
A particle of mass 100 g is thrown vertically upward with a speed of 5 m/s. The work done by the force of gravity during the time the particle goes up is
-0.5 J
-1.25 J
1.25 J
0.5 J
Solution
B.
-1.25 J
The height (h) transversed by particle while going up is
n =
n =
Work done by gravity force = mg.h
= 0.1 × g × cos 180o
(angle between force and displacement is 180)
∴ W = - 0.1 ×
W = -1.25 J
