A 1990 kg car moving at 20.0 m/s collides and locks together with a 1540 kg car at rest at a stop sign. Show that momentum is conserved in a reference frame moving at 10.0 m/s in the direction of the moving car.

The momentum before collision and momentum after collision is equal in a frame of reference moving at 10.0 m/s in the direction of the moving car.

Explanation:

= Mass of moving car = 1990 kg

= Velocity of moving car in stationary frame = 20 m/s

= Mass of stationary car = 1540 kg

= Velocity of stationary car in stationary frame = 0 m/s

v = Combined velocity in stationary frame

Momentum conservation for stationary frame

In frame moving at 10 m/s the velocities change in the following ways

Momentum before collision

Momentum after collision

The momentum before collision and momentum after collision is equal. So, the momentum is conserved in a reference frame moving at 10.0 m/s in the direction of the moving car.

8 meters above the spring

50 inches should be the resultant vector