Which one of the following is not a zero vector or a null vector ?

Options

A. The displacement of a stone thrown upwards and received back by the thrower
B. The displacement of a particle along the circumference of a circle of radius r when it goes from one point on the circle to its diametrically opposite point
C. The acceleration vector of a body moving with uniform velocity along a straight line
D. The displacement of a stationary object from time `t_(1)=1` minute to time `t_(2)=4` minute

Answer

B

Explanation

In (a), the displacement is zero but the distance travelled is not zero.
In (d), the object is at rest. Hence its displacement is zero, whatever may be the time interval.
In (c ), for a body moving with a uniform velocity, the acceleration is zero.
In (b), the body has a displacement =2r and the distance travelled `=pi`. The displacement vector is not a null vector.