Do solid particles vibrate?
a. no.
b. yes, they vibrate about a fixed point.
c. yes, they vibrate about a low velocity, moving point.
d. yes, they vibrate about a high velocity, moving point.

The answer to this question about solid particles would be B. Yes, they vibrate about a fixed point.

It is important to remember that the basic difference of the 3 states of matter is how their molecules are arranged. Gas molecules are situated far from each other which gives the molecules space to freely move around giving the gas its characteristics. Liquid molecules, on the other hand, are situated near to each other, where there is still space that let's them move but not as free as gas molecules. Solid molecules are very close to each other that the phrase tightly packed is but an understatement. This is also a reason that when solid particles vibrate, usually when heated, it is only about a fixed point.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j