4. A worker exerts 140 N to push a 15 kg crate 20 meters across the floor. He then lifts the crate 2 meters up to a shelf.
a. How much work is done to push the crate across the floor?
b. What work was done to lift the crate up?
c. What was the total work done by the worker?

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

If element x has 99 protons how many electrons does it have

During the apollo moon missions, astronauts were concerned about the effects of newton's third law of motion when: o a. they ejected waste water, because they were concerned that it would push them off course. o b. they reentered earth's atmosphere, because they were carrying heavy moon rocks. o c. they took off from earth, because a large force was required to generate large acceleration. o d. they detected incoming space debris, because the inertia of the debris could damage their ship.