Q. A particle moving along a straight line has a velocity $v\ ms^{- 1}$, when it cleared a distance of $y$ metre. These two are connected by the relation $v = \sqrt{49 + y}$. When its velocity is $1$ $ms^{- 1},$ its acceleration (in $ms^{- 2}$)is

A) 1
B) 2
C) 7
D) 0.5
Explanation

(d) $v = \sqrt{49 + y},a = \frac{dv}{dy}.\frac{dy}{dt} = v\frac{dv}{dy}$
$= (49 + y)^{1/2} \times \frac{1}{2}(49 + y)^{1/2 - 1}$= $\frac{1}{2}ms^{- 2}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.