Q. A bridge is in the form of a semi-circle of radius 40 m. The greatest speed with which a motor cycle can cross the bridge without leaving the ground at the highest point is$\ \left( g = 10{ms}^{- 2} \right)\ $(frictional force is negligibly small)
A) $40\ {ms}^{- 1}$
B) $20\ {ms}^{- 1}$
C) $30\ {ms}^{- 1}$
D) $15\ {ms}^{- 1}$
Explanation
(b) $Given,\ r = 40\ m\ and\ g = 10{m/s}^{2}$
$we\ have\ \ \ v = \sqrt{gr}$
$= 10 \times 40 = \sqrt{400}$
$= 20\ m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.