Question

A vehicle of mass 600kg, moving at a speed of 30ms^-1 collides with a stationary vehicle of mass 900kg. The two vehicles lock together on impact.

Calculate:

1) The speed of the two vehicles immediately after the impact.

2) The force of the impact, if the duration of the collision is 0.15s.

3) The acceleration of each vehicle during the impact.

Answer 1

1. M1*V1 + M2*V2 = M1*V + M2*V.
600*30 + 900*0 = 600V * 900V,
18000 = 1500V, V = 12 m/s.

2. V = Vo + a*t.
12 = 30 + a*0.15, a = -120 m/s^2.

F = M*a = (M1+M2)*a = 1500 * (-120) = -180,000 N.
The negative sign means the force opposed the motion.

3. a = -120 m/s^2.