Question

Find range of projectile on the inclined plane which is projected perpendicular to the inclined plane with velocity 20 m/s as shown in figure :

• A. $55m$
• B. $75m$
• C. $84m$
• D. $100m$

Answer 1

Answer: (B)

$75m$

Components of initial velocity
$u_x=u\cos (\theta +\alpha )$
$u_y=u\sin (\theta +\alpha )$
Components of acceleration
$a_x=g\sin \alpha ;a_y=-g\cos \alpha$
Time of flight$T=\frac{2u\sin (\theta +\alpha )}{g\cos \alpha }$
$\therefore$ Range of flight$=R=\frac{u^2}{g\cos \alpha }\{\sin (2\theta +\alpha )+\sin \alpha \}$
$u=20\frac{m}{s},\theta =37°,\alpha =(90-37)°=53°,g=10㎨$
$\therefore$ We get $R=75m$