two vehicles have a head on collision. one vehicle has a mass of 3000 kg and moves at 25 m/s while the second vehicle has a mass of 2500 kg and moves at - 15 m/s. if the vehicles stick together after the collision what is the speed of the combined vehicles

The speed of the combined vehicles is 6.82m/s

Explanation:

Using the law of conservation of momentum which stayed that the sum of momentum of bodies before collision is equal to their sum of momentum after collision. After collision, both object moves with the same velocity.

Momentum = mass*velocity

Before collision:

Momentum of vehicle or mass 3000kg moving with velocity 25m/s

= 3000*25

= 75000kgm/s

Pa = 75000kgm/s

Momentum of vehicle with mass 2500kg moving with velocity of - 15m/s

= 2500*-15

= - 37500kgm/s

After collision:

Momentum = (3000+2500) V

Where v is their common velocity

Momentum after collision = 5500V

Based on the law:

75000 + (-37500) = 5500V

75000-37500 = 5500V

37500 = 5500V

V = 37500/5500

V = 6.82m/s