Question

When the force and the displacement are in the opposite directions, the work done by the force is ..........

• A. $positive$
• B. $negative$
• C. $zero$
• D. $notformthis$

Answer 1

The correct option is B $negative$

Work done by the force,

$W=\overrightarrow{F}.\overrightarrow{r}=Frcos\theta$. . . . . . . .(1)

If the force and the displacement are in the opposite direction, then angle between the force and the displacement is ${180}^0$

$cos\theta =cos{180}^0=-1$

from equation (1),

$W=-Fr$

The work done by the force is negative.

The correct option is B.