Question

A shell is fired from a gun from the bottom of a hill along its slope. The slope of the hill is α = 30^o, and the angle of the barrel to the horizontal β = 60^o. The initial velocity v of the shell is 21 m/sec. Then distance of point from the gun at which shell will fall

• A. 10 m
• B. 20 m
• C. 30 m
• D. 40 m

Answer 1

Answer: (C)

30 m

Answer 2

Here u = 21 m/sec, α = 30⁰, θ = β – α = 60⁰ – 30⁰ = 30⁰

Maximum range $R = \frac{2u^{2}}{g}\frac{\sin\theta\cos(\theta + \alpha)}{\cos^{2}\alpha}$

$= \frac{2 \times (21)^{2} \times \sin 30^{o}\cos 60^{o}}{9.8 \times \cos^{2}30^{o}} = 30m$