Question

Range of a projectile is $R$, when the angle of projection is $30$. Then, the value of the otherangle of projection for the same range, is :

• A. $45$
• B. $60$
• C. $50$
• D. $40$

Answer 1

Answer: (B)

$60$

If two bodies thrown at same speed at angles such that their sum =π/2 then both of them will have the same range. (Because due to this value of sin(2$\theta$) will not change. )
so the other angle has to be $90-30={60}^o$