Atennis player hits a 1.45 kg tennis ball with a racket of mass 2.5 kg. if he hits the ball with a velocity of 7.5 m/s and then stops, what impulse did he imply on the ball? what is the ball’s velocity?

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

To a of 4 x hz is 1. 0. mm nm nm

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.