What happens to the motion of an object when the forces acting on it are balanced? a. the motion changes. b. the motion does not change. c. the motion speeds up. d. the motion slows down.

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.