Question

Describe the motion of a body where the directions of its velocity and acceleration are opposite to each other?

• A. Velocity will increase continuosly till acceleration becomes zero.
• B. Velocity will decrease only till the object comes to rest.
• C. Velocity will decrease to zero, then it will start moving in the direction of acceleration.
• D. Velocity will be changing but its speed will be the same.

Answer 1

The correct option is C Velocity will decrease to zero, then it will start moving in the direction of acceleration.

From definition of acceleration,
$a=\frac{v-u}{t}$
where:
v: Final velocity
u: Initial velocity
t: Time taken
$⟹v=u+at$
If acceleration is negative,
$v=u-at$ So, velocity will decrease in magnitude and eventually become zero, after which it will start moving in the direction of acceleration.