Question

The range of a projectile when fired at ${75}^{\circ }$ with the horizontal is $0.5$ km. what will be its range when fired at ${45}^{\circ }$ with same speed:

• A. $0.5$ km
• B. $1.0$ km
• C. $1.5$ km
• D. $20$ km

Answer 1

The correct option is B $1.0$ km

$R_1=\frac{u^{2}sin150}{g}=\frac{u^{2}sin(180-30)}{g}=\frac{u^{2}sin30}{g}=\frac{u^2}{2g}=0.5$

$R_2=\frac{u^{2}sin90}{g}=\frac{u^2}{g}=2R_1=1.0km$