a tractor of mass 5.0×10^3kg is used to tow a car of mass 2.5×10^3kg. The tractor moved with a speed of 3.0m/s just before the towing rope became taut.
1. Find the speed of the tractor immediately the rope becomes taut
2. loss in kinetic energy of the system just after the car has started moving
3. impulse in the rope when it jerks the car into motion
1. conservation of momentum: 5e3*3=(5+2.5)e3* v solve for v
2. KeLoss=initial-final=1/2 * 5e3*3^2 -1/2 (5+2.3)e3*v^2