Q. A solid sphere rolls down two different inclined planes of same length, but of different inclinations. In both cases
A) Speed and time of descent will be same
B) Speed will be same, but time of descent will be different
C) Speed will be different, but time of descent will be same
D) Speed and time of descent both are different
Explanation
(b) In pure rolling, mechanical energy remains conserved. Therefore, when heights of inclines are equal, speed of sphere will be same in both the cases. But as acceleration down the incline, $a \propto \sin\theta$ therefore, acceleration and time of descent will be different
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.