Q. The range of particle when launched at an angle $15{^\circ}$ with the horizontal is 1.5 km. What is the range of projectile when launched at an angle of $45{^\circ}$ to the horizontal?
A) 3.0 km
B) 1.5 km
C) 6.0 km
D) 0.75 km
Explanation
(a) $The\ horizontal\ range\ R_{x} = \frac{u^{2}\sin{2\theta}}{g}$
When projected at angle of $15{^\circ}$
$R_{x1} = \frac{u^{2}}{g}\sin{(2 \times 15) = \frac{u^{2}}{2g} = 1.5km\ }$
When projected at angle of $45{^\circ}$
$R_{x1} = \frac{u^{2}}{g}\sin{(2 \times 45{^\circ})\frac{u^{2}}{g}}$
$= \frac{{2u}^{2}}{2g} = 2 \times 1.5 = 3.0\ km$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.