Question

A force of magnitude $F_1$ acts on a particle so as to accelerate it from rest to a velocity $v$. The force $F_1$ is then replaced by $F_2$ which decelerates it to rest. So:

• A. $F_1$ must be equal to $F_2$
• B. $F_1$ may be equal to $F_2$
• C. $F_1$ must be unequal to $F_2$
• D. none of these

Answer 1

The correct option is C $F_1$ must be unequal to $F_2$

Force is a vector quantity. For two vectors to be equal both magnitudes and directions should be the same. In this case, one force accelerates the particle and other force deaccelerates it so their directions should not be the same