What are the two families of fundamental particles out of which all ordinary matter is made?
A) protons and neutrons
B) leptons and quarks
C) electrons and neutrinos
D) quarks and neutrinos
E) leptons and photons
B) leptons and quarks
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Kepler's first law of planetary motion states "The orbits of the planets are _____ with the Sun at one focus."
a. spheres b. ellipses c. circular d. rigid e. random
A 25.0-V potential source (a battery) is connected across the plates of a 6.66-µF air-filled parallel-plate capacitor having plates that are 1.22 mm apart
What energy density does it produce between the plates? (?0 = 8.85 × 10-12 C2/N ? m2)
The observed evidence we have for black holes includes
A) X-rays that are thought to come from the center of a black hole. B) visible light that is thought to come from the center of a black hole. C) temperature measurement of certain extremely cold stars that are thought to be black holes. D) X-rays that are thought to come from gases that are outside of a black hole. E) observations of certain regions of space, larger than the largest known stars, that emit no light.
A truck is carrying a 120-kg refrigerator, which is 2.20 m tall and 85.0 cm wide has its center of mass at its geometrical center
The refrigerator is facing sideways and a short strip on the bed of the truck keeps the refrigerator from sliding. What is the maximum acceleration that the truck can have before the refrigerator begins to tip over? A) 1.90 m/s2 B) 4.17 m/s2 C) 3.79 m/s2 D) 7.58 m/s2 E) 8.34 m/s2