Question

A body will have zero acceleration when:
A) the force acting on it decreases
B) Its velocity changes in direction
C) Its velocity changes in magnitude
D) Its velocity has same magnitude and direction​

Answer 1

Answer:

option D

Explanation:

hope it's helpful

Answer 2

Answer:

A body will have zero acceleration when its velocity has the same magnitude and direction​ i.e.option(D).

Explanation:

For force, we know that,

$Force=mass\times acceleration$     (1)

And for acceleration, we know that,

$Acceleration=\frac{Velocity}{time}$                (2)

Now let's analyze the options one by one

(A) The force acting on it decreases-this does not imply that acceleration is zero. It indicates that acceleration is decreasing and it will not be zero. So, this option is wrong.

(B)Its velocity changes in direction-this means that acceleration is also changing its direction e.g.uniform circular motion. So, this option is also wrong.

(C) Its velocity changes in magnitude-this mean that acceleration is also changing its magnitude (from equation 2). So, this option is also wrong.

(D)Its velocity has the same magnitude and direction​-this means there is also no change in direction as well as the magnitude of acceleration. Hence, in this case, the acceleration will be zero.

Hence, a body will have zero acceleration when its velocity has the same magnitude and direction​ i.e.option(D).