A car has a forward force acting on it due to the firing of its engine. If the car is moving at a constant speed, then A. An equal force is pushing it backward

B. A second forces pushing it forward

C. No other forces are acting on it

D. All lesser forces pushing it backward

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. when the carts collide, they hook together. assume that positive momentum is to the right. which graph best represents the momentum of both carts over time, before and after the collision?