Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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Determine the work done by lifting a 140 pound bag of sugar 12 feet.
a. | 1,680 ft-lb | b. | 16,800 ft-lb | c. | 2,600
ft-lb | d. | 168 ft-lb | e. | 260 ft-lb |
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2.
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A force of 10 pounds compresses a 21-inch spring 8 inches. How much work is done
in compressing the spring from a length of 15 inches to a length of 13 inches?
a. | 22.5 ft-lb | b. | 19.5 ft-lb | c. | 17.5
ft-lb | d. | 12.5 ft-lb | e. | 27.5 ft-lb |
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3.
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A force of 265 Newtons stretches a spring 20 centimeters. How much work is done
in stretching the spring from 15 centimeters to 25 centimeters?
a. | 28.5 joules | b. | 31.5 joules | c. | 26.5
joules | d. | 21.5 joules | e. | 36.5 joules |
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4.
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A force of 20 pounds stretches a spring 11 inches in an exercise machine. Find
the work done in stretching the spring 2 feet from its natural position.
a. |  ft-lb | b. | 
ft-lb | c. |  ft-lb | d. | 
ft-lb | e. |  ft-lb |
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5.
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An overhead garage door has two springs, one on each side of the door. A force
of 12 pounds is required to stretch each spring 1 foot. Because of the pulley system, the springs
stretch only one-half the distance the door travels. The door moves a total of 10 feet and springs
are at their natural length when the door is open. Find the work done by pair of strings.
a. | 150 ft-lb | b. | 300 ft-lb | c. | 2,400
ft-lb | d. | 1,200 ft-lb | e. | 600 ft-lb |
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6.
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Neglecting air resistance and the weight of the propellant, determine the work
done in propelling a six-ton satellite to a height of 200 miles above earth. Assume that Earth has a
radius of 4000 miles.
a. |  ft-lb | b. | 
ft-lb | c. |  ft-lb | d. | 
ft-lb | e. |  ft-lb |
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7.
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Neglecting air resistance and the weight of the propellant, determine the work
done in propelling a 12-ton satellite to a height of 100 miles above Earth. Assume that the Earth has
a radius of 4000 miles.
a. | 1,756.10 mi-ton | b. | 1,170.73 mi-ton | c. | 702.44
mi-ton | d. | 936.59 mi-ton | e. | 2,575.61
mi-ton |
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8.
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A lunar module weighs 16 tons on the surface of Earth. How much work is done in
propelling the module from the surface of the moon to a height of 50 miles? Consider the radius of
the moon to be 1100 miles and its force of gravity to be one-sixth that of Earth.
a. |  ft-lb | b. | 
ft-lb | c. |  ft-lb | d. | 
ft-lb | e. |  ft-lb |
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9.
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A tank with a base of 4 feet by 3 feet and a height of 4 feet is full of water.
The water weighs 62.4 pounds per cubic foot. How much work is done in pumping water out over the top
edge in order to empty half of the tank. Round your answer to one decimal place.  a. | 499.2 ft-lb | b. | 748.8 ft-lb | c. | 5,990.4
ft-lb | d. | 1,996.8 ft-lb | e. | 1,497.6 ft-lb |
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10.
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A cylindrical water tank 5 meters high with a radius of 2 meters is buried so
that the top of the tank is 1 meter below ground level. How much work is done in pumping a full tank
of water up to ground level? (The water weighs 9800 newtons per cubic meter.)
a. | 548,800 joules | b. | 705,600 joules | c. | 411,600
joules | d. | 1,234,800 joules | e. | 1,029,000 joules |
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11.
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An open tank has the shape of a right circular cone. The tank is 9 feet across
the top and 8 feet high. How much work is done in emptying the tank by pumping the water over the top
edge? Note: The density of water is 62.4 lbs per cubic foot.
a. | 9,466.31 ft-lb | b. | 4,043.52 ft-lb | c. | 5,391.36
ft-lb | d. | 10,108.80 ft-lb | e. | 12,130.56 ft-lb |
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12.
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A 17-foot chain that weighs 4 pounds per cubic foot hangs from a winch 17 feet
above ground level. Find the work done by the winch in winding up the entire chain.
a. | 346.80 ft-lb | b. | 1,040.40 ft-lb | c. | 867.00
ft-lb | d. | 462.40 ft-lb | e. | 578.00 ft-lb |
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13.
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A quantity of gas with an initial volume of 8 cubic feet and a pressure of 1500
pounds per square foot expands to a volume of 10 cubic feet. Find the work done by the gas for the
given volume and pressure. Round your answer to two decimal places.
a. | 1,606.63 ft-lb | b. | 4,016.58 ft-lb | c. | 4,819.90
ft-lb | d. | 2,677.72 ft-lb | e. | 2,142.18 ft-lb |
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14.
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A quantity of a gas with an initial volume of 1 cubic foot and a pressure of
2000 pounds per square foot expands to a volume of 7 cubic feet. Find the work done by the gas. Round
your answer to two decimal places.
a. | 3,841.82 ft-lb | b. | 3,891.82 ft-lb | c. | 1,714.29
ft-lb | d. | 1,959.18 ft-lb | e. | 3,583.52 ft-lb |
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15.
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Two electrons repel each other with a force that varies inversely as the square
of the distance between them, where k is the constant of proportionality. One electron is
fixed at the point  . Find the work done in moving the second
electron from  to  . a. |  units of work | b. | 
units of work | c. |  units of work | d. | 
units of work | e. |  units of work |
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