While Robert was helping his father in the garden, he pushed a shovel into the ground to dig a hole in the dirt. He picked up a shrub, carried it to the hole, and held it while he lowered it into the hole. During which parts of this process does Robert NOT do work? Choose the two statements that apply.
A. He pushed a shovel into the ground to dig a hole.
B. He picked up a shrub.
C. He carried it to the hole
D. He held it while he lowered it into the hole

Avery hard rubber ball (m = 0.5 kg) is falling vertically at 4 m/s just before it bounces on the floor. the ball rebounds back at essentially the same speed. if the collision with the floor lasts 0.05 s, what is the average force exerted by the floor on the ball?

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.

Madison pushes with a 210-n horizontal force on a 24-kg crate of coffee resting on a warehouse floor. the force of friction on the crate is 74 n. what is the acceleration?