Approximately how long does it take the sun to go through a full cycle of passing above and below the plane of the galaxy?
A) a few million years B) a few tens of millions of years
C) a few thousand years D) a few hundred years
B
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A strobe photograph of a car moving along a straight road shows the interval between each successive image to be diminishing. If the direction of motion of the car is taken as positive, which of the following is/are negative?
a. the speed of the car b. the average velocity of the car c. the average acceleration of the car d. all of the above
A straight 10-cm wire bent at its midpoint so as to form an angle of 90° carries a current of 10 A. It lies in the xy plane in a region where the magnetic field is in the positive z direction and has a constant magnitude of 3.0 mT. What is the magnitude of the magnetic force on this wire?
a. 3.2 mN b. 2.1 mN c. 5.3 mN d. 4.2 mN e. 6.0 mN
Which pair of ball-drop experiments will best test whether mass affects the acceleration of gravity?
Exp 1. Mass 0.5 kilograms, height 20 meters Exp 2. Mass 5.0 kilograms, height 20 meters Exp 3. Mass 0.5 kilograms, height 30 meters A) Exp 1 and 3 B) Exp 1 and 2 C) Exp 2 and 3
How is a luminosity class assigned to a star?
a. by combining the apparent magnitude with the star's parallax b. by measuring the period of variability in the star's apparent magnitude c. by studying the absorption line width in the spectrum of the star d. by observing the angular size of the star's image in a photograph or digital image