Question

Two ships A and B are stationary, facing away from each other. Ship A has a cannon at its back which

fires shell's with a speed of 10 m/s. Initially they are at a distance 5√3 m apart. Find the maximum and

minimum angle with which the shells should be projected from ship A to hit ship B. The ships are of

equal length 10(5-√2)​

Answer 1

Given that,

Distance $d=5\sqrt{3}\ m$

Speed of shell = 10 m/s

If the shell fires end of the ship A and it is hit the end of the ship B.

We need to calculate the angle

Using formula of range

$R=\dfrac{u^2\sin2\alpha}{g}$

Put the value into the formula

$5\sqrt{3}=\dfrac{10^2\sin2\theta}{9.8}$

$\sin2\theta=\dfrac{5\sqrt{3}\times9.8}{10^2}$

$\sin2\theta=0.848$

$2\theta=\sin^{-1}(0.848)$

$\theta=\dfrac{57.9}{2}$

$\theta=28.95^{\circ}$

Hence, The angle is 28.95°.