A cart rolls with low friction on a track. A fan is mounted on the cart, and when the fan is turned on, there is a constant force acting on the cart. Three different experiments are performed: (a) Fan off: The cart is originally at rest. You give it a brief push, and it coasts a long distance along the track in the x direction, slowly coming to a stop. (b) Fan forward: The fan is turned on, and you hold the cart stationary. You then take your hand away, and the cart moves forward, in the x direction. After traveling a long distance along the track, you quickly stop and hold the cart. (c) Fan backward: The fan is turned on facing the "wrong" way, and you hold the cart stationary. You give it a brief push, and the cart moves forward, in the x direction, slowing down and then turning around, returning to the starting position, where you quickly stop and hold the cart.