Question

barge of mass M is at rest and tied to the pier by a cable. a car of mass m is at rest at left end of the barge as shown in the figure. a workman, of negligible mass, drives the car with a constant acceleration from the left to the right end. the car attains a speed vc in a time T when it reaches the right end of the barge. assume that the barge does not move while the car is moving from left to right. question: is the velocity of the center of mass of the car + barge system constant?

Answer 1

The sum of the external forces on the system is equal to the force exerted on the barge by the cable, then the acceleration of the center of mass is not zero and the velocity of the center of mass is not constant.