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–1, at what speed does the bullet hit the thief’s car? (Note: Obtain that speed which is relevant for damaging the thief’s car).
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–1, at what speed does the bullet hit the thief’s car? (Note: Obtain that speed which is relevant for damaging the thief’s car).
Given, that the speed of the police van and the bullet is 30 km/h and 192 km/h respectively, and the muzzle speed of the bullet is 150 m/s.
The speed of the bullet is equal to the sum of the speed of a van and the muzzle speed of the bullet. Therefore, the speed of a bullet is,
vb =30 km/h +150 m/s =30× 518 m/s +150 m/s = 4753 m/s
Let the speed of the thief’s car be vc.
The speed of the bullet with which it hit the thief’s car is,
v= vb − vc
Here, v c is the speed of the car.
Substitute the values in the above expression.
v= 4753 m/s −192 km/h = 4753 m/s −192×518 m/s =105 m/s
Hence, the speed of the bullet at which it hits the thief’s car is 105 m/s.
Given, that the speed of the police van and the bullet is 30 km/h and 192 km/h respectively, and the muzzle speed of the bullet is 150 m/s.
The speed of the bullet is equal to the sum of the speed of a van and the muzzle speed of the bullet. Therefore, the speed of a bullet is,
vb =30 km/h +150 m/s =30× 518 m/s +150 m/s = 4753 m/s
Let the speed of the thief’s car be vc.
The speed of the bullet with which it hit the thief’s car is,
v= vb − vc
Here, v c is the speed of the car.
Substitute the values in the above expression.
v= 4753 m/s −192 km/h = 4753 m/s −192×518 m/s =105 m/s
Hence, the speed of the bullet at which it hits the thief’s car is 105 m/s.
