Question

A ball moves on a smooth floor in a straight line with 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 the same speed. Draw the velocity-time graph and use it to find the total distance travelled by the ball and its displacement.

Answer 1

Distance travelled in first 6 s = velocity × time

= 10 m/s × 6

= 60 m

Distance travelled in next 6 s = velocity × time

= 10 m/s × 6

= 60 m

Total distance travelled in 12 s = (60 + 60) m = 120 m

Total displacement = 0, as the ball returns its starting point.