Question

Question: On seeing enemy ships at a distance of 125 m from the shore, the canons start firing fireballs. The captain of the ship saw the cannon fire. He knows the velocity of the fireballs is 50 m/s. Now in how much time does he have to steer his ship in some other direction so as to save his crew. Use angle of projection as ${30}^o$. Also find the maximum height that the fireball reaches above water.

Answer 1

u = 50 m/s, θ = ${30}^o$
∴Time of flight, T = 2u sinθ/g
=$2\times 50\times \sin {30}^{\circ }/10$
= 2 ×50/2×10
= 5 s
Maximum Height, H = $u^2{\sin }^2\theta /2g$
= $\left(50{)}^2{\sin }^2\right({30}^o\left)/2\right(10)$
= 31.25 m.

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