Question

A police jeep is chasing with, velocity of $45\frac{km}{h}$ a thief in another jeep moving with velocity $153\frac{km}{h}$. Police fires a bullet with muzzle velocity of $180\frac{m}{s}$. The velocity it will strike the car of the thief is

• A. $150\frac{m}{s}$
• B. $27\frac{m}{s}$
• C. $450\frac{m}{s}$
• D. $250\frac{m}{s}$

Answer 1

The correct option is A $150\frac{m}{s}$

Effective speed of the bullet
= speed of bullet + speed of police jeep
$=180\frac{m}{s}+45\frac{km}{h}=(180+12.5)\frac{m}{s}=192.5\frac{m}{s}$
Speed of thief ’s jeep = $153\frac{km}{h}=42.5\frac{m}{s}$
Velocity of bullet w.r.t thief's car = $192.5-42.5=150\frac{m}{s}$