Q. The time taken by a block of wood (initially at rest)to slide down a smooth inclined plane $9.8\ m$ long (angle of inclination is $30{^\circ}$) is
A) $\frac{1}{2}\sec$
B) $2sec$
C) $4sec$
D) $1sec$
Explanation
(b) For one dimensional motion along a plane
$S = ut + \frac{1}{2}at^{2} \Rightarrow 9.8 = 0 + \frac{1}{2}g\sin{\ 30{^\circ}t^{2}} \Rightarrow t = 2\sec$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.