Because the Hubble constant has a value of 70 km/s/Mpc, a galaxy with a recession velocity of 21,000 km/s must be _______________ Mpc from Earth. (Express your answer as a whole number of Mpc)

Fill in the blank(s) with correct word


300

Physics & Space Science

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If you are at the South Pole and are standing straight then your head points up to nadir and your feet point down to zenith

a. True b. False Indicate whether the statement is true or false

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An 800-kHz radio signal is detected at a point 9.1 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.440 V/m

Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the average total power radiated by the transmitter? (c = 3.00 × 108 m/s, ?0 = 4? × 10-7 T ? m/A, ?0 = 8.85 × 10-12 C2/N ? m2) A) 0.27 MW B) 0.32 MW C) 0.38 MW D) 0.45 MW E) 0.50 MW

Physics & Space Science

If the density of the universe is lower than the critical density, this means that:

A) the universe is expanding at a rate equal to the escape speed of the universe. B) the universe is expanding at a rate less than the escape speed of the universe. C) the universe is expanding at a rate greater than the escape speed of the universe. D) the universe is expanding at a rate equal to the speed of light. E) the universe is expanding at a rate greater than the speed of light.

Physics & Space Science

A fire hose is turned on the door of a burning building in order to knock the door down. This requires a force of 1000. N

If the hose delivers 40. liters per second, what is the maximum velocity of the stream needed, assuming the water doesn't bounce back? A) 50. m/s B) 25 m/s C) 40. m/s D) 15. m/s E) 30. m/s

Physics & Space Science