A ball moves on a smooth floor in a straight line with a uniform velocity 10 m s^-1 for 6 s. At t = 6 s, the ball hits a wall and comes back along the same line to the starting point with same speed. Draw the velocity-time graph and use it to find the total distance travelled by the ball and its displacement.

Figure shows the velocity-time graph of a particle moving in a straight line.

(i) State the nature of motion of particle.

(ii) Find the displacement of particle at t = 6 s.

(iii) Does the particle change its direction of motion?

(iv) Compare the distance travelled by the particle from 0 to 4 s and from 4 s to 6 s.

(v) Find the acceleration from 0 to 4 s and retardation from 4 s to 6 s.

If a body is moving with a uniform retardation, then its acceleration will be:

1. Positive
2. Negative
3. Zero
4. Cannot say

A car acquires a velocity of 54 ms^-1 in 20 s starting from rest, then its acceleration is:

1. 5.4 ms^-2
2. 2.7 ms^-2
3. 7.2 ms^-2
4. 2.0 ms^-2