A police van moving on a highway with a speed of 30 km/h fires a bullet at a thief’s car speeding away in the same direction with a speed of 192 km/h. If the muzzle speed of the bullet is 150 m/s, with what speed does the bullet hit the thief’s car? (Note: Obtain that speed which is relevant for damaging the thief’s car).
Given,
Speed of the police van = 30 km/h = 8.33 m/s
Speed of the thief’s car = 192 km/h = 53.33 m/s
Speed of the bullet = 150 m/s
Initial speed of the bullet is given by,
U = Speed of the bullet + Speed of the police van
= 150 + 8.33 = 158.33 m/s
Since, both bullet and thief’s car moving in same direction, relative velocity of the bullet with respect to thief’s car is given by,
Vbt = U – Speed of the thief’s car
= 158.33 – 53.33 = 105 m/s
Hence, The bullet hits the thief’s with a speed of 105 m/s