Question: In case of negative work, the angle between the force and displacement is
(a) $0^{\circ}$
(b) $45^{\circ}$
(c) $90^{\circ}$
(d) $180^{\circ}$.
Solution:
(d) Explanation: $W=F S \cos \theta .$ When $\theta=180^{\circ}, \cos 180^{\circ}=-1$ and $W=-F S$
