John and Haven move a large bookcase from the bedroom to the living room. The bookcase has a mass of 45 kg. They apply a force of 300 N to move the bookcase 8 m. It takes them 20 seconds to move the bookcase a. How much work do they do to move the bookcase? b. What is their power?

Apossible explanation for a set of facts that can be tested by further investigation is called

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

Aball tossed vertically upward from the ground next to a building passes the bottom of a window 1.8 s after being tossed and passes the top of the window 0.20 s later. the window is 2.0 m high from top to bottom. what was the ball's initial velocity? the unit vector j^ is directed upward. how far is the bottom of the window from the launch position? how high does the ball rise above the launch position?