An observer's nadir is
a. the point directly opposite the observer's zenith.
b. the north point on the observer's horizon.
c. located at the center of Earth.
d. always located near a circumpolar constellation.
e. directly opposite the north celestial pole.
a
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Electrons can be transferred from one place to another by the process of
A) friction. B) contact, which means touching. C) induction, which means non-touching. D) all of the above E) none of the above
Calories of the food type are equal to which of the following?
a. 4.186 J b. 4 186 J c. 1 BTU d. 1054 J
Bert says that a charged particle in a vacuum can travel in a helix only if a uniform electric field and a uniform magnetic field are both present and both parallel to the axis of the helix. Stuart says that only a magnetic field with a component parallel to the axis of the helix is needed. Which one, if either, is correct, and why?
a. Bert, because the charged particle's velocity can have a vertical component only if an electric field in the vertical direction is present. b. Stuart, because a component of velocity in the vertical direction is not changed by a vertical component of a magnetic field. c. Bert, because a component of velocity in the vertical direction is changed by a vertical component of a magnetic field. d. Stuart, because an electric field in the vertical direction would cause the particle to come to a complete stop. e. Neither, because particles cannot move in helical paths in the presence of magnetic and electric fields.
A scuba diver has his lungs filled to half capacity (3 liters) when 10 m below the surface. If the diver holds his breath while quietly rising to the surface, what will the volume of the lungs be (in liters) at the surface? Assume the temperature is the same at all depths. (The density of water is 1.0 × 10^3 kg/m3.)
a. 5.9 b. 4.5 c. 6.4 d. 3.9 e. 3.1