Question

A ball moves in the direction of the arrow labelled $\mathbf{c}$in Figure $\mathbf{2}\mathbf{.}\mathbf{53}$The ball is struck by a stick that briefly exerts a force on the ball in the direction of the arrow labelled $\mathbf{e}$. Which arrow best describes the direction of $\mathbf{∆}\mathbf{p}$, the change in the ball's momentum?

Short answer

The correct direction of the ball's momentum change is $\mathrm{e}$.

Step-by-step solution

Action of force applied perpendicularly on a moving object

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.

Represent the situation diagrammatically

• The body's motion is circular in this case, 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 are depicted in the diagram below.