Question

A $2 \,kg$ toy car can move along an $x$ axis. Graph shows force $F_{x}$, acting on the car which begins at rest at time $t=0$ The velocity of the particle at $t=10\,s$ is :

• A. $-i\,m/s$
• B. $-1.5\,i\,m/s$
• C. $6.5\,i\,m/s$
• D. $13\,i\,m/s$

Answer 1

Answer: (C)

$\int dp=P_{f} -P_{i} =\int F\,dt $
= Area under the curve
$P_{i}=0$
Net Area $=16-2-1=13\,N-s$
$=V_{f}=\frac{13}{2}=6.5i \,m /s$
[As momentum is positive, particle is moving along positive x axis]