A tennis ball with a speed of 20.7 m/s is moving perpendicular to a wall. After striking
the wall, the ball rebounds in the opposite
direction with a speed of 13.8276 m/s.
If the ball is in contact with the wall for
0.00828 s, what is the average acceleration of
the ball while it is in contact with the wall?
Take "toward the wall” to be the positive
direction.
Answer in units of m/s2.

An uncharged nonconductive hollow sphere of radius 18.0 cm surrounds a 12.0 µc charge located at the origin of a cartesian coordinate system. a drill with a radius of 1.00 mm is aligned along the z axis, and a hole is drilled in the sphere. calculate the electric flux through the hole.

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Amoving company collects data about couches they move and displays the data in a table. the force along the ramp, the angle of the ramp, and the height the couch is raised to are shown. which statements correctly compare the work done to move the couches? check all that apply. the same amount of work is done for couches 1 and 3. the same amount of work is done for couches 2 and 3. the work for couch 1 is greater than the work for couch 2. the work for couch 2 is less than the work for couch 3. the work for couch 3 is greater than the work for couch 1. the work for couch 2 is greater than the work for couch 1.