Question : 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)
Doubt by Kartik
Solution :
Velocity of Police Van (VP) = 30 km/h
= 30×(5/18) m/s
= (25/3) m/s
Velocity of thief's car (VT) = 192 km/h
= 192×(5/18) m/s
= (160/3) m/s
Muzzle Speed of the Bullet (VM) = 150 m/s
Total velocity of the Bullet (VB)
=Velocity of police Van (VP) + Muzzle speed of Bullet (VM)
= (25/3 + 150)
= (25+450)/3
= 475/3 m/s
Velocity of bullet with which it hits the thief's car
= Relative velocity of bullet w.r.t. thief's car
= VB-VT
= (475/3)-(160/3)
= 315/3
= 105 m/s