Asilver bar 0.125 meter long is subjected to a temperature change from 200°c to 100°c. what will be the length of the bar after the temperature change?

a. 0.189 meterb. 0.2363 meterc. 0.124764 meterd. 0.00023635 meter

The answer is C C. 0.124764 meters. When a metal (or almost any item save water) is cooled, it shrinks, as the atoms that make it up vibrate less and less and causes the item to contract. The reverse happens when heating, as the atom vibrate faster causing it to expand. Now, even though it would shrink, the shrinkage would not be that noticeable to the naked eye, and thus, the other lengths are just FAR too short to occur.

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