Q. A body of mass 10 kg is moving with a constant velocity of $10\ {ms}^{- 1}.$ When a constant force acts for 4 s on it, it moves with velocity $2\ {ms}^{- 1}$ in the opposite direction. The acceleration produced in it is
A) $3\ {ms}^{- 2}$
B) $- 3\ {ms}^{- 2}$
C) $0.3\ {ms}^{- 2}$
D) $- 0.3\ {ms}^{- 2}$
Explanation
(b) $\ \ \ \ \ \ \ \ \ v = u + at$
$\Rightarrow \ - 2 = 10 + a \times 4$
$\therefore\ \ \ \ \ a = - 3\ {ms}^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.