question_answer 19)

Suggest a suitable physical situation for each of the following graphs [Fig. 3.89]:        (a)     (b) (c)   Fig. 3.89  

Answer:

(a) A ball lies at rest on a smooth floor, as indicated by straight line PQ of the x-t graph. It is kicked towards a wall. Slope of line QR gives speed of kicking. The ball rebounds from the wall with a reduced speed (given by the slope of line RS). At S, the sign of position coordinate changes sign, it indicates that the ball moves to the opposite wall which stops it. The line TU indicates the final rest position of the ball. (b) The velocity-time graph represents the motion of a ball thrown up with some initial velocity, it hits the ground and gets rebounded with a reduced speed. It goes on hitting the ground and after each hit its speed decreases unit it becomes zero and the ball comes to rest finally. (c) The acceleration-time graph represents the motion of a uniformly moving cricket ball turned back by hitting it with a bat for a very short time interval.