Question

Two canons installed at the top of a cliff 10 m high fire a shot each with speed 5√3 ms^-1 at some interval. One canon fires at 60° with horizontal whereas the second fires horizontally. The coordinates of point of collision of shots are

• A. 3 √5, 3m
• B. 1/5√3 m, 1/5 m
• C. 1/3 m, 1/3√5 m
• D. 5√3m, 5m

Answer 1

Answer: (D)

5√3m, 5m

Answer 2

Let t₁ and t₂ be the times of shot from cannot at 60^o and the slot from horizontal cannot to reach the point of collision.

∴ x = (5√3 cos 60)t₁ = 5√3 t₂

and y = 10 + 5√3 sin 60t₁ – 1/2 gt₁² = 10 – 1/2 gt₂²