A ball moves in the direction of the arrow labeledin Figure. The ball is struck by a stick that briefly exerts a force on the ball in the direction of the arrow labeled. Which arrow best describes the direction of, the change in the ball's momentum?

When a body moves in a specific direction at a specific velocity and an external force acts on it in a perpendicular direction to its motion, the body's speed remains constant, but its direction of motion changes.

• The body's motion is circular, and the velocity vector is always tangential to the circular path on which it moves.
• In this example, a force acted on the body in an inward direction, which is responsible for the body's circular trajectory.
• The direction of velocity change is the same as the direction of momentum change.
• The force applied by the stick and the ball's initial velocity is depicted in the diagram below as,

• The ball moves in the direction of, whereas the force moves in the direction of e.
• As a result, the direction of acceleration is along, and the change in velocity direction is also along e .
• The direction of change in velocity is the same as the change in momentum, as it is well known. As a result, momentum will flow in the direction of e .
• As a result, the right direction of the ball's momentum changes is,e.