A radar signal bounces off your car and back to the antenna of a policeman's radar gun, checking for speeders. The radar gun can tell your speed of approach by "listening" for and measuring
A. a reflected signal at a higher frequency.
B. a reflected signal at a lower frequency.
C. a reflected signal with zero frequency.
D. a reflected signal at the same frequency but polarized.
Answer: A
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Which of the following correctly lists the described speeds from slowest to fastest?
A) Earth's orbital speed about the Sun Earth's speed of rotation on its axis Earth's orbital speed about the Sun typical speeds of stars in the local solar neighborhood relative to us the speed of our solar system orbiting the center of the Milky Way Galaxy the speeds of very distant galaxies relative to us B) typical speeds of stars in the local solar neighborhood relative to us Earth's speed of rotation on its axis Earth's orbital speed about the Sun the speed of our solar system orbiting the center of the Milky Way Galaxy the speeds of very distant galaxies relative to us C) Earth's speed of rotation on its axis Earth's orbital speed about the Sun the speed of our solar system orbiting the center of the Milky Way Galaxy the speeds of very distant galaxies relative to us typical speeds of stars in the local solar neighborhood relative to us D) Earth's orbital speed about the Sun the speeds of very distant galaxies relative to us Earth's speed of rotation on its axis typical speeds of stars in the local solar neighborhood relative to us the speed of our solar system orbiting the center of the Milky Way Galaxy E) typical speeds of stars in the local solar neighborhood relative to us the speed of our solar system orbiting the center of the Milky Way Galaxy Earth's orbital speed about the Sun the speeds of very distant galaxies relative to us Earth's speed of rotation on its axis
Three different-mass projectiles are launched at different angles of elevation from the top of a building. Each particle has the same initial kinetic energy. Which particle has the greatest kinetic energy just as it impacts with the ground?
a. The one launched at the highest angle of elevation. b. The one with the highest mass. c. The one with the lowest mass. d. They all will have the same kinetic energy on impact.
Which of the above would best describe how soap behaves in water?
A) a B) b C) c D) d E) none of the above
A spaceship is moving past us at a speed close to the speed of light. What would we conclude about time (clocks) on the spaceship as it goes by?
A) Time is the same for everyone. B) We would conclude that their clocks are going at the same rate as ours. C) We would conclude that their clocks are going exactly half as fast as ours. D) We would conclude that their clocks are going faster than ours. E) We would conclude that their clocks are going slower than ours.