In the brushless DC exciter, the commutator of a conventional direct-connected exciter is replaced with a threephase, bridge-type, ____.
a. solid-state rectifier
b. controlled rectifier
c. direct transformer
d. small rectifier
a. solid-state rectifier
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The phases of a construction project begin with _____, continue with _____, and finish with _____.
a. development; preconstruction; construction b. development; design; construction c. design; development; construction d. design; construction; closeout
Two students want to measure the acceleration a of a cart rolling down an inclined plane. The cart starts at rest and travels a distance s down the plane. The first student estimates the acceleration by measuring the instantaneous velocity v just as the cart has traveled s meters, and uses the formula 
The second student estimates the acceleration by measuring the time, in seconds, that the cart takes to travel s meters, and uses the formula 
. Assume that s=1 m, and that there is negligible uncertainty in s. Assume that v=3.2 ± 0.1 m/s and that t=0.63 ± 0.01 s. Assume that the measurements of v and t are independent.
a. Compute the acceleration using the method of the first student. Call this estimate 
. Find the uncertainty in .
b. Compute the acceleration using the method of the second student. Call this estimate 
. Find the uncertainty in .
c. Find the weighted average of 
and 
that has the smallest uncertainty. Find the uncertainty in this weighted average.
Industrialization of agriculture refers to integration throughout the food chain and brings into question the survival of the family farm
Indicate whether the statement is true or false
____ lubrication is the condition in which the friction between two surfaces that are in motion is determined by the properties of the surfaces and the properties of the lubrication that is being used, excluding viscosity.
A. Barrier B. Boundary C. Film D. Residual