Question

The figure shows the position - $time\, (x - t)$ graph of one-dimensional motion of a body of mass $0.4\, kg$. The magnitude of each impulse is

• A. 0.4 Ns
• B. 0.8 Ns
• C. 1.6 Ns
• D. 0.2 Ns

Answer 1

Answer: (B)

From the graph, it is a straight line so, uniform motion. Because of impulse direction of velocity changes as can be seen from the slope of the graph.
Initial velocity $= \frac{2}{2} = 1\,m/ s$
Final velocity $=- \frac{2}{2} = -1\,m/ s$
$\overrightarrow{P_{i}} = 0.4 \,N -s$
$\overrightarrow{Pj_{i}} = 0.4 \,N -s$
$\vec{J} = \overrightarrow{P_{f}} - \overrightarrow{P_{i}} = -0.4-0.4 = -0.8\,N-s$ ($\vec{J}$ = impulse)