Question

A canon elevated at an angle of ${15}^o$, throws a shell with a muzzle speed of $196{ms}^{-1}$. Due to air resistance the range decreased by $100$ m, then what is the observed range ?

• A. $1960$ m
• B. $1860$ m
• C. $2000$ m
• D. $1660$ m

Answer 1

The correct option is B $1860$ m

Given : $u=196m/s$ $\theta ={15}^o$

Range of the shell $R=\frac{u^2\sin 2\theta }{g}$

$⟹R=\frac{u^2\sin 30}{g}=\frac{196\times 196\times 0.5}{9.8}=1960m$

Due to air resistance, the observed range decreases by 100 m.

Thus, observed range $R_{observed}=1960-100=1860m$