Positive work can be done
a. by friction on the tires when a car is accelerating without skidding.
b. by a spring when it launches a clown in the air.
c. by a hand throwing a ball.
d. by all of the above.
e. only by (b) and (c) above.
e
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The radius of a circle is increased by 5%. The percentage increase of the circumference is
A. 5%. B. 10%. C. 12%. D. 16%.
The ratio of the specific heat of a gas at constant volume to its specific heat at constant pressure is:
A. 1 B. less than 1 C. more than 1 D. has units of pressure/volume E. has units of volume/pressure
Instructions: On occasion, the notation 
= [A, ?] will be a shorthand notation for 
.
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Exhibit 3-4
The diagram below shows the path taken by a sailboat tacking sideways because it cannot sail directly into the wind.
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Use this exhibit to answer the following question(s).
Refer to Exhibit 3-4. The total distance it travels is
A. 1000 m.
B. 1732 m.
C. 2000 m.
D. 6298 m.
E. 8000 m.
A 80. volt DC motor draws 4.0 A at its operating speed of 1500. rpm with an armature resistance of 4.0 ?
(a) What is the starting current? (b) What is the back emf when running normally? (c) What series resistance could be added to limit the starting current to 10. A?