Q. The initial velocity of a body moving along a straight line is $7\ m/s$. It has a uniform acceleration of $4\ m/s^{2}$. The distance covered by the body in the $\ 5^{th}$ second of its motion is
A) 25 $m$
B) 35$\ m$
C) 50$\ m$
D) 85$\ m$
Explanation
(a) $S_{n} = u + \frac{a}{2}\lbrack 2n - 1\rbrack$
$S_{5^{th}} = 7 + \frac{4}{2}\lbrack 2 \times 5 - 1\rbrack = 7 + 18 = 25m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.