The following changes all require ____: mechanical movement, the production of heat or light, the production of sound, the conversion of one chemical compound into another, and the production of radio waves.
a. energy
b. measurement
c. joules
d. resistance heating
a. energy
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When the sampling frequency equals with the accompanying image, the sample-and-hold operation maintains the sample value for _____ (xx.x) ?s.
Fill in the blank(s) with the appropriate word(s).
Answer the following statement(s) true (T) or false (F)
1. In a squirrel cage motor, the rotor is constructed of steel laminations mounted rigidly on the motor shaft. 2. Locked rotor currents for different motor types vary from 10 to 20 times the full-load current of the motor. 3. Slip refers to the twisting or turning of the motor shaft. 4. By reducing the starting voltage, at the motor terminals, the starting torque is decreased. 5. With impedance starting, reactors are used in series with the motor.
If two sides of a triangular lot are 90 feet and 120 feet and meet at a 90-degree angle, the length of the third side of the lot is _____.
a. 120 feet b. 150 feet c. 180 feet d. 240 feet
A balanced three-phase source furnishes power to the following three loads:
Load 1: 1 kVA at 0.83 pf lagging Load 2: unknown Load 3: 8 kW at 0.7071 pf leading If the line current is 84.6 A (rms), the line voltage at the load is 208 V (rms), the combined load has a 0.8 pf lagging, determine the unknown load.