____ of white southerners owned slaves or belonged to a slaveholding family.
A. One-fourth
B. One-third
C. Half
D. Fifteen percent
E. Five percent
Answer: A
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____ is a thermoset elastomeric compound produced from propylene, ethylene, and diene monomer.
A. Ethylene propylene diene monomer B. Polyvinyl chloride C. Chlorosulfated polyethylene D. Styrene-butadiene-styrene
How many lighting fixtures are connected to Circuit A-4 in Figure 2?
a. Twenty Type A
b. Ten Type D and nine Type C
c. Eleven Type A and two Type B
d. Eight Type C
How much end play is generally acceptable in tie rod ends?
A) Zero B) 0.050 to 0.100 in. C) 0.0010 to 0.030 in. D) 0.030 to 0.050 in.
An electromagnet is used to support a solid piece of steel, as shown in Example 18.9. A force of 10,000 N is required to support the weight. The cross-sectional area of the magnetic core (the fixed part) is 0.01 m2. The coil has 1,000 turns. Determine the minimum current that can keep the weight from falling for x = 1.0 mm. Assume negligible reluctance in steel and negligible fringing in the air gaps.
Example 18.9
An electromagnet is used to collect and support a solid piece of steel, as shown in Figure 18.38. Calculate the starting current required to lift the load and the holding current required to keep the load in place once it has been lifted and is attached to the magnet. Assume that the cross-sectional areas of the electromagnet, load (bar), and air gap are equal.
Assumptions:
Negligible reluctance for the steel parts and negligible fringing in the air gaps.