A 300-kg truck moving rightward with a speed of 5 km/hr collides head on with a 1000kg car moving leftward with a speed of 100 km/hr. The two vehicles stick together and move with the same velocity after the collision determine the post - collision speed of the car and truck

The final velocity of the vehicles will be -75km per hour (leftwards).

Explanation:

Let us call , mass and velocity of the truck , mass and velocity of the car, and the final velocity of the vehicles.

The law of conservation of momentum states that

solving for we get:

putting in numerical values

(the negative sign indicates that the vehicles are moving in the leftward direction)

or -75.8 km per hour.

newton's first law of motion