Question

Plss help me!!

A navy ship observes an illigal boat 'd' miles away to it's West. If the boat travels at a 'u' velocity towards the south , and it's given that the maximum velocity of the ship's canon is λu ( λ<1)
and the max range they can be shot at is 'v',
show that if λ^2 +(v/d)^2 <1 ,
1) that the illigal boat can avoid any harm caused by the navy ship.
( use relative velocity triangles and geometry)​

Answer 1

Explanation:

The problem statement says λ<1. If this is true, then the cannonball is slower than the boat, and it will never reach the boat. So I assume it's actually λ>1.

If we say t is the amount of time, then the boat travels south a distance of ut, and the cannonball travels a distance of λut.

v = λut

ut = v/λ

Using Pythagorean theorem:

d² + (ut)² > v²

d² + (v/λ)² > v²

λ²d² + v² > λ²v²

λ²d² > (λ² − 1) v²

λ² / (λ² − 1) > (v/d)²