Question

A police van moving on a highway with a speed of $30km{h}^{-1}$ fires a bullet at a thief’s car speeding away in the same direction with a speed of $192km{h}^{-1}$. If the muzzle speed of the bullet is $150m{s}^{-1}$, with what speed does the bullet hit the thief's car? (Note: Obtainthat speed which is relevant for damaging the thief's car).

Answer 1

Speed of the police van, $v_p$ = 30 km/h = 8.33 m/s
Muzzle speed of the bullet, $v_b$ = 150 m/s
Speed of the thief's car, $v_t$ = 192 km/h = 53.33 m/s
Since the bullet is fired from a moving van, its resultant speed can be obtained as:
= 150 + 8.33 = 158.33 m/s
Since both the vehicles are moving in the same direction, the velocity with which the bullet hits the thief's car can be obtained as:
$v_{bt}=v_b–v_t$ = 158.33 – 53.33 = 105 m/s