Q.
A particle of mass $2\ kg$ is initially at rest. A force acts on it whose magnitude changes with time. The force time graph is shown below
The velocity of the particle after $10\ s$ is
A) $20\ ms^{- 1}$
B) $10\ ms^{- 1}$
C) $75\ ms^{- 1}$
D) $50\ ms^{- 1}$
Explanation
(d) Velocity after $10\ \sec. = \frac{1}{m}$
Area enclosed between $F - t$ graph and time axis
Area $= \frac{1}{2}\left\lbrack \frac{1}{2} \times 2 \times 10 + 2 \times 10 + \frac{1}{2} \times 30 \times 2 + \frac{1}{2} \times 4 \times 20 \right\rbrack$
$= 50\ m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.