A large 700 kg truck is driving with a speed of 20 m/s when it collides with a 300 kg car which is not moving. The two stick together. After the collision will the car and truck will have a speed Less than, Greater than. or Equal to 20 m/s?
1 Answer
Jan 11, 2017
The final speed after collision must be less than 20 m/s if momentum is to be conserved. In fact, it will be 14 m/s as explained below.
Explanation:
Before the collision, only the 700 kg truck has momentum (the car is not moving)
After the collision, the combined mass of the two joined vehicles is 1000 kg, but the total amount of momentum must still be 14 000 kgm/s.
So the final speed must be