Notice the well-defined spiral arms in this photograph of the galaxy M51. What makes the spiral arms so much brighter than regions between the arms?
A) the presence of many massive young stars in the spiral arms
B) the presence of many old, red giant stars in the spiral arms
C) the presence of many hot interstellar bubbles in the spiral arms
D) The spiral arms are bright because nearly all the galaxy's stars are located within them.
A) the presence of many massive young stars in the spiral arms
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Which is not an example of approximate simple harmonic motion?
a. A ball bouncing on the floor. b. A child swinging on a swing. c. A piano string that has been struck. d. A car's radio antenna as it waves back and forth.
A force applied to an object will always cause the object to
a. speed up b. accelerate c. change its momentum d. all of the above e. none of the above
The north pole of a compass points toward Earth's magnetic ______________ pole
Fill in the blank(s) with correct word
The lamps in a string of Christmas tree lights are connected in parallel. What happens if one lamp burns out? (Assume negligible resistance in the wires leading to the lamps.)
A) The brightness of the lamps will not change appreciably. B) The other lamps get brighter equally. C) The other lamps get brighter, but some get brighter than others. D) The other lamps get dimmer equally. E) The other lamps get dimmer, but some get dimmer than others.