Question

Two balls A and B are thrown with speeds u and u/2 respectively. Both the balls cover the same horizontal distance before returning to the plane of projection. If the angle of projection of ball B is 15^° with the horizontal, then the angle of projection of A is :

(A) (1/2) sin^-1 (1/8)

(B) (1/4) sin^-1 (1/8)

(C) (1/3) sin^-1 (1/8)

(D) sin^-1 (1/8)

Answer 1

The correct option is A.

Solution :

​​​​For A, R = \(\frac{u^2 sin\theta}{g}\)

For B, R = \(\frac{u^2}{8g}\)

Comparing; \(\)\(sin2\theta = \frac 1 8\)

\(\Rightarrow\theta = \frac 1 2 sin^1\frac 1 8\)