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Sample Practice Test Questions
What's the last gear in a gear train called?
driven gear
A gear train is two or more gears linked together. Gear trains are designed to increase or reduce the speed or torque outpout of a rotating system or change the direction of its output. The first gear in the chain is called the driver and the last gear in the chain the driven gear with the gears between them called idler gears.
A joint created by welding is __________ the original metal.
as strong or stronger than
The joint created by welding is as strong or stronger than the original metal.
An endoskeleton (internal skeleton) is a charateristic of __________ animals, including humans.
vertebrate
An endoskeleton (internal skeleton) is a charateristic of vertebrate animals, including humans.
Heat is always transferred from __________ to __________ environments.
warmer, cooler
Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.
Depending on where you apply effort and resistance, the wheel and axle can multiply:
force or speed
If you apply the resistance to the axle and the effort to the wheel, the wheel and axle will multiply force and if you apply the resistance to the wheel and the effort to the axle, it will multiply speed.
Work is measured in:
joules or newton-meters
Work is performed on an object when an applied force causes displacement along the same vector. Measured in joules (J) or newton-meters (Nm), work is calculated by multiplying force times displacement: \(W = \vec{F}\vec{d}\)
What is the primary difference between a rectifier and an inverter?
a rectifier converts an AC input to DC while an inverter converts a DC input to AC
A diode allows current to pass easily in one direction and blocks current in the other direction. Diodes are commonly used for rectification which is the conversion of alternating current (AC) into direct current (DC). Because a diode only allows current flow in one direction, it will pass either the upper or lower half of AC waves (half-wave rectification) creating pulsating DC. Multiple diodes can be connected together to utilize both halves of the AC signal in full-wave rectification.