question_answer 45)

                    A ball is dropped and its displacement vs time graph is as shown Fig. (displacement \[x\] is from ground and all quantities are +ve upwards).                 (a) Plot qualitatively velocity vs time graph.                 (b) Plot qualitatively acceleration vs time graph.                

Answer:

    When ball is dropped, it falls under the action of gravity alone if air resistance is neglected. The ball will fall with a constant acceleration \[=-g\]. (a) As \[x\] increases with time, slope of \[x-t\]graph is positive. At the peak of the curve, slope of \[x-t\] graph is zero, so \[\upsilon =0\]. As curve declines, slope of \[x-t\] graph is negative, so \[\upsilon \]is negative.