Consider a situation where you carry a 20 N box up a flight of stairs, raising its elevation by 5 m. The increase of potential energy of the box is
a. 0 c. 100 J
b. 4 J d. none of the above
C
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In a liquid at a given temperature, the molecules are moving in every direction, some fast, some slowly. Electrical forces of adhesion tend to hold them together
However, occasionally one molecule gains enough energy (as a result of collisions) so that it pulls loose from its neighbors and escapes from the liquid. Which of the following can best be understood in terms of this phenomenon? A) Increasing the atmospheric pressure over a liquid will cause the boiling temperature to decrease. B) If snow begins to fall when you are skiing, you will feel colder than you did before it started to snow. C) When a large steel suspension bridge is built, gaps are left between the girders. D) When you step out of a swimming pool and stand in the wind, you will get colder than you would if you stayed out of the wind. E) A hot water bottle will do a better job of keeping you warm than will a rock of the same mass heated to the same temperature.
In the light curve below, what is the period of the eclipsing binary?
a.
5 days
b.
32.5 days
c.
7.5 days
d.
42.5 days
e.
50 days
Which of these are English units?
a. seconds b. feet c. kilometers d. slugs
An _________in crystallinity in a polymer increases the yield strength.
Fill in the blank(s) with the appropriate word(s).