Preston pushes a wheelbarrow weighing 480 N to the top of a 45.0-m ramp, inclined at 22.0° with the horizontal, and leaves it. Tamara accidentally bumps the wheelbarrow. It slides back down the ramp, during which an 85.0-N frictional force acts on it over the 45.0 m. What is the wheelbarrow's kinetic energy at the bottom at of the ramp? (g = 9.8 m/s2)
a. 1.4E+3 J
b. 1.6E+4 J
c. 1.2E+4 J
d. 8.1E+3 J
e. 4.3E+3 J
e
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If Q = 80 nC, a = 3.0 m, and b = 4.0 m in the figure, what is the magnitude of the electric field at point P?
a.
45 N/C
b.
70 N/C
c.
29 N/C
d.
47 N/C
e.
92 N/C
In a cyanine dye molecule, one electron is free to move up and down along a linear chain of carbon atoms, but cannot pass the nitrogen atoms at each of the chain’s ends. Assume that the length of the chain does not change much as we increase the electron’s energy (within reasonable limits). Which of the idealized models in this chapter might best describe the electron in this situation?
A. The quanton in a box model B. The Bohr model C. The simple harmonic oscillator model
A magnifying glass uses a converging lens with a refractive power of 20 diopters. What is the angular magnification if the image is to be viewed by a relaxed eye with a near point of 25 cm?
A) 5.0 B) 3.0 C) 4.0 D) 1.0 E) 2.0
A chunk of ice (T = -20°C) is added to a thermally insulated container of cold water (T = 0°C). What happens in the container?
A) The ice melts until thermal equilibrium is established. B) The water cools down until thermal equilibrium is established. C) Some of the water freezes and the chunk of ice gets larger. D) none of the above