1.A9,700-kgtruck runs into the rear of a1,000-kgcar that was stationary. The truck and car are locked together after the collision and move with speed2m/s.What was the speed of the truck before the collision?

2.In compressing the spring in a toy dart gun,0.8Jof work is done. When the gun is fired, the spring gives its potential energy to a dart with a mass of0.07kg.

a.What is the dart's kinetic energy as it leaves the gun?

b.What is the dart's speed?