What is the key distinction between protostars and true (main-sequence) stars?
A) Protostars generate most of their energy from gravitational contraction, and stars generate it from nuclear fusion.
B) Protostars are larger and more luminous than stars.
C) Protostars have stronger magnetic fields than stars.
D) Protostars are supported by thermal pressure, and stars are supported by degeneracy pressure.
A) Protostars generate most of their energy from gravitational contraction, and stars generate it from nuclear fusion.
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Uniform Electric Fields: Consider a uniform horizontal electric field of 50 N/C directed toward the east. If the electric potential at a given point in the field is 80 V, what is the potential at a point 1.0 m directly east of the point?
A. 15 V B. 30 V C. 90 V D. 130 V
How does an accretion disk around a neutron star differ from an accretion disk around a white dwarf?
A) The accretion disk around a neutron star is much hotter and emits higher-energy radiation. B) The accretion disk around a neutron star is made mostly of helium, while the accretion disk around a white dwarf is made mostly of hydrogen. C) The accretion disk around a neutron star is more likely to give birth to planets. D) The accretion disk around a neutron star always contains much more mass.
T2 = kR3 is known as ______________
Fill in the blank(s) with correct word
A small boat is moving at a velocity of 3.35 m/s when it is accelerated by a river current perpendicular to the initial direction of motion. If the acceleration of the current is 0.750 m/s2, what will be the new velocity of the boat after 33.5 s?
A) 25.3 m/s at 82.4° from initial direction of motion B) 25.3 m/s at 7.59° from initial direction of motion C) 640.1 m/s at 82.4° from initial direction of motion D) 640.1 m/s at 7.59° from initial direction of motion