Most people reject what they don’t understand because a. it is too expensive to change b. it challenges their own ideas c. it must either be rejected or it must be accepted d. it is humiliating to try to understand something

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)