Question

A motorcyclist starts from the bottom of a slope of angle ${45}^o$ to cross the valley PR as shown in the figure. The width of the valley is 90 m and length of the slope is $80\sqrt{2M}.$ The minimum velocity at point O required to clear the valley will be

• A. 70 m/s
• B. 30 m/s
• C. 50 m/s
• D. 100 m/s

Answer 1

The correct option is C 50 m/s

$\theta ={45}^{\circ }$, Width = 90 m

Length = $80\sqrt{2}$

$v^2=900$

$v=30m{s}^{-1}$

How along the incline declaration = $g\sin {45}^{\circ }$

$u^2-v^2=2\times g\sin {45}^{\circ }\times 80\sqrt{2}$

$u=50m{s}^{-1}$