The visual pink glow of the Great Nebula in Orion
a. is a Herbig-Haro object.
b. is a reflection nebula of dust.
c. is an emission nebula of thin gas.
d. contains only young low mass stars.
e. is believed to be about 5 billion years old.
C
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The energy to extend a crack in a stressed material comes from _________of stresses along the crack surface.
Fill in the blank(s) with the appropriate word(s).
Consider a conducting bar that is free to slide along conducting rails in an upward magnetic field as shown in the diagram below. We push the bar so that it moves to the right at a constant speed. Which way will current flow through the bar, the rails, and the light bulb?
A. Clockwise
B. Counter-clockwise
C. No current flows at all.
The loops shown below are immersed in a uniform magnetic field parallel to the plane of the drawing. (The step vector shown is a typical one for each loop.)
A. 
B. 
C. 
D. 
E. E
A car travels in a due northerly direction at a speed of 55 km/h. The traces of rain on the side windows of the car make an angle of 60 degrees with respect to the horizontal. If the rain is falling vertically with respect to the Earth, what is the speed of the rain with respect to the Earth?
a. 48 km/h b. 95 km/h c. 58 km/h d. 32 km/h e. 80 km/h