Question

Figure ahead represents the displacement - time sketch of motion of two cars A and B . Find : 
(i) the distance by which the car B was initially ahead of car A.
(ii) the velocities of car A and car B.
(iii) the time in which car A catches car B.
(iv) the distance from start when the car A will catch the car B.

Answer 1

(i) Initially, the car B was 40 km ahead of car A.

(ii) Straight line depicts that cars A and B are moving with uniform velocities.

For car A

Displacement at t = 1 h is 40 m

Velocity = Displacement /time

 = (40/1) km/h

 = 40 km/h^-1

 

For car B

Displacement at t = 4 h is (120 - 40) km, i.e. 80 km

Velocity = Displacement /time

 = (80/4) km/h

 = 20 km/h^-1

 

(iii) Car A catches car B in 2 hours.

(iv) After starting, car A will catch car B at 80 km.