A freight train rolls along a track with considerable momentum. Impulses are smaller when bounces take place. A karate expert executes a swift blow and severs a cement block with her or his bare hand. The impulse on both the block and the expert's hand have the same magnitude.
Rockets do accelerate in outer space.
In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Paul D. Trigger fires a bullet. Three books, X, Y, and Z, rest on a table as shown in the diagram at the right. The weight of each book is indicated. The net or unbalanced force acting on book Y is a. 4 N down.