How many types of fundamental particles are there in the Universe and how many dominate on Earth?
A. About 30 with 3 dominant
B. More than a million with 3 dominant
C. About 300 with 30 dominant
D. About 300 with 3 dominant
E. About 30 with 15 dominant
Ans: A. About 30 with 3 dominant
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What are the different colored horizontal layers that we see in this photo of a wall in the Grand Canyon?
A) They are sediments deposited at different times in the past, so that layers near the bottom are the oldest and layers near the top are the youngest. B) They are different types of volcanic rock that cooled at different rates after a single, large volcanic eruption. C) They formed as the Colorado River carved out the canyon, so that the layers near the top are the oldest and the layers at the bottom are the youngest. D) They got their coloration from ancient civilizations that painted the rock.
A film of index of refraction n1 coats a surface with index of refraction n2. When n1>n2, the condition for destructive interference for reflected monochromatic light of wavelength ? in air is
A.
.B.
.C.
.D.
.E.
.A skydiver who weighs 500 N reaches terminal velocity at 90 km/h. The air resistance on the skydiver is
A) 90 N. B) 250 N. C) 410 N. D) 500 N. E) none of the above
As a 1.0-kg object moves from point A to point B, it is acted upon by a single conservative force which does ?40 J of work during this motion. At point A the speed of the particle is 6.0 m/s and the potential energy associated with the force is +50 J. What is the potential energy at point B?
a. +72 J b. +10 J c. +90 J d. +28 J e. +68 J