This Hubble Space Telescope photo shows a planetary nebula. What is the white dot in the center (indicated by the arrow)?
A) a white dwarf
B) a red giant star with a strong stellar wind
C) a neutron star
D) a protostar that will soon become a main-sequence star
A) a white dwarf
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Intensity of Sound: If the intensity level of one trombone is 70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all playing simultaneously in the same place?
A. 146 dB B. 89 dB C. 70 dB D. 76 dB E. 82 dB
Exhibit 13-1
Two blocks of masses m1 and m2 are connected by a light cord that passes over a pulley of mass M, as shown. Block m2 slides on a frictionless horizontal surface. The blocks and pulley are initially at rest. When m1 is released, the blocks accelerate and the pulley rotates.
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Use this exhibit to answer the following question(s).
Refer to Exhibit 13-1. The total angular momentum of the system of the two blocks and the pulley relative to the axis of rotation of the pulley is
A. the same at all times. B. proportional to l1, the length of string from the pulley to m1. C. proportional to l2, the length of string from the pulley to m2. D. conserved because the Earth doesn't move. E. proportional to the speed of the blocks.
Each night you measure your height just before going to bed
When you arise each morning, you measure your height again and consistently find that you are 1 inch taller than you were the night before but only as tall as you were 24 hours ago! Is what happens to your body in this instance best described as a physical change or a chemical change? A) chemical change because it involves your body B) physical change because it readily reverses C) chemical change because it involves changes in your bone structure D) physical change because water expands as it freezes
A 200-g hockey puck is launched at an initial speed of 16 m/s up a metal ramp that is inclined at a 30° angle. The coefficients of static and kinetic friction between the hockey puck and the metal ramp are µs = 0.40 and µk = 0.30, respectively
What vertical height does the puck reach above its starting point? A) 17 cm B) 13 cm C) 4.2 cm D) 8.6 cm