The range of projectile is 1 .5 km when it is projected at an angle of 15° with horizontal. What will be its range when it is projected at an angle of 45° with the horizontal?
(A) 0.75 km
(B) 1.5 km
(C) 3 km
(D) 6 km
Correct Option is (C) 3 km
We knoe that , range of projectile
\(R = \frac{u^2 sin \ 2 \ \theta}{g}\)
\(1.5 = \frac{u^2 sin(2 \times 15)}{g}\)
\(1.5 = \frac{u^2}{2g}\)
\(\frac{u^2}{g} = 3\)
when, \(\theta = 45^\circ\)
\(R = \frac{u^2 sin^2 \theta}{g}\)
\(R = \frac{u^2}{g} \times sin (2 \times 45)\)
\(R = \frac{u^2}{g}\)
R = 3 km