Q 11-04-031JEE MainAIEEE 2010Hard
The position-time graph of a body of mass $0.04$ kg is shown in the figure. The time between two consecutive impulses received by the body and the magnitude of each impulse is
Answer: (B) $2$ s, $8 \times 10^{-4}$ kg m/s
The graph is made of straight lines: the body moves with constant speed $\dfrac{2\ \text{cm}}{2\ \text{s}} = 1$ cm/s $= 0.01$ m/s and reverses direction every $2$ s (at $t = 2, 4, 6, \dots$ s).
Each reversal is caused by an impulse. The velocity changes from $+0.01$ to $-0.01$ m/s (or back):
$$J = m\,\Delta v = 0.04 \times 0.02 = 8 \times 10^{-4}\ \text{kg m/s}$$
Time between consecutive impulses: $2$ s.
Solution by Sreeraj P, M.Sc Physics