If you just stand still on an escalator (moving stairway), it takes 20 s for it to carry you up one floor, about 5 m. But if youwalk up, you get to the top of the escalator in only 12 s. A. How much work does the escalator do in lifting you up to the next floor, if you just stand there?B. How much if you walk up? C. Some people expect the answer in part (b) to be the same as in part (a), saying that the escalator is still exerting the same force over the same distance; some people expect it to be more, saying that when your walk up your feet press down harder on the stairs than the do if you just stand, so the force is greater; and some people expect it should be less, saying that you're expending energy, so the escalator must expend less. Explain the problem with the reasoning by the folks who have it wrong.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.