A \(1200-\mathrm{kg}\) car is backing out of a parking space at \(5.0 \mathrm{~m} / \mathrm{s}\). The unobservant driver of a \(1800-\mathrm{kg}\) pickup truck is coasting through the parking lot at a speed of \(3.0 \mathrm{~m} / \mathrm{s}\) and runs straight into the rear bumper of the car.

(a) What is the change in internal energy of the twovehicle system if the velocity of the pickup is \(1.5 \mathrm{~m} / \mathrm{s}\) backward after they collide? \((b)\) What is the coefficient of restitution for this collision?