The ionosphere reflects high frequency radio waves
Indicate whether the statement is true or false
F
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The largest elliptical galaxies are likely the product of galactic mergers. The largest elliptical galaxies are likely the product of galactic mergers.
Indicate whether the statement is true false.
Vision Problems: A farsighted boy has a near point at 2.3 m and requires contact lenses to correct his vision to the normal near point. What is the correct choice of lens power for the contact lenses?
A. -0.28 diopters B. +0.28 diopters C. -3.6 diopters D. +3.6 diopters E. +1.8 diopters
A 3.0-kg mass is dropped from the edge of a 50-m tall building with an initial speed of zero. The mass strikes the ground with a downward velocity of 25 m/s. Find the change in mechanical energy of the mass caused by air resistance between the point where it is dropped and the point where it strikes the ground.
A. ?0.46 kJ B. ?0.53 kJ C. ?0.61 kJ D. ?0.38 kJ E. ?0.81 kJ
What technique often requires the use of a laser guide star?
a. active optics b. photometry c. adaptive optics d. comparison spectrum e. representational color imaging