An empty train car moving at 21 m/s collides with a loaded train car initially at rest that has twice the mass of the empty car. The two cars couple together. a) What is the final velocity of the cars after the collision? 7 m/s
b) Is kinetic energy conserved in this collision? If so, how do you know? If not, why is there a difference?

To protect all four receptacles on a branch circuit that surrounds a swimming pool, you would install which of the following configurations? a. gfci feed-through receptacle at the end of the load's circuit b. gfci-terminated receptacle at the beginning of the load's circuit c. gfci feed-through receptacle at the beginning of the load's circuit and the other receptacles connected to the load side of that receptacle d. gfci-terminated receptacle at each end of the load's circuit

At the negative terminal of the battery the electron has electric potential energy. what happens to this energy as the electron jumps from the negative to the positive terminal?

How is the acceleration of an object in uniform circular motion constant? a - in magnitude only b - in direction only c - in both magnitude and direction d - in magnitude, direction & orientation