Process of Science: The theory of spiral arms explain why short-lived, massive stars are found there but longer-lived, low mass stars should last for many orbits around a galaxy and therefore be much more spread out
How might you test that prediction?
Low mass stars are redder than high mass stars so observations at red wavelengths should have a lower contrast in and out of spiral arms that observations at blue wavelengths.
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Velma, who is moving past you at a high rate of speed, holds a meter stick and a standard kilogram
Is it possible that your measurements could show the standard kilogram to have a mass of 2 kg while the meter stick still has its normal length of 1 m? A) Yes, if Velma holds the meter stick parallel to its direction of motion. B) Yes, if Velma holds the meter stick perpendicular to its direction of motion. C) No, because mass actually decreases with velocity, rather than increasing. D) No; if the kilogram's mass has increased to 2 kg, then it must be longer than 1 m. E) No; if the kilogram's mass has increased to 2 kg, then it must be shorter than 1 m.
A cylindrical capacitor is made of two concentric cylinders. The inner cylinder has radius r1 = 4 mm, and the outer one a radius r2 = 8 mm. The common length of the cylinders is L = 150 m
What is the potential energy stored in this capacitor when a potential difference V = 4 V is applied between the inner and outer cylinder? A) 9.6 × 10-8 J B) 1.3 × 10-8 J C) 6.3 × 10-8 J D) 0.34 × 10-8 J E) 4.6 × 10-8 J
A catcher stops a 0.15-kg ball traveling at 40 m/s in a distance of 20 cm. What is the magnitude of the average force that the ball exerts against his glove?
What will be an ideal response?
Which fundamental fact about the electromagnetic force explains why electromagnetic waves exist, rather than simply electromagnetic force?
A) The electromagnetic force acts at a distance with a delay time, rather than instantaneously. B) The electromagnetic force decreases at points more distant from the source of that force. C) The electromagnetic force can be felt in all directions from the source of that force. D) The electromagnetic force cannot be felt across vacuum. E) The electromagnetic force acts instantaneously at a distance, with no delay time.