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Electronics Information

This circuit component symbol represents a(n):

resistor

Resistors are used to limit voltage and/or current in a circuit and can have a fixed or variable resistance. Variable resistors (often called potentiometers or rheostats) are used when dynamic control over the voltage/current in a circuit is needed, for example, in a light dimmer or volume control.

Mechanical Comprehension

What is the first step to solving a problem where multiple forces are acting on an object?

calculate the net force

In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.

Electronics Information

Which of the following will increase the magnetic field produced by the electric current in a wire?

wind the wire into a coil

A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.

Automotive Information

Which of the following is not a function of antifreeze?

lubricates the cooling system

Modern car engines are cooled by liquid which circulates through the engine block and cylinder heads absorbing excess heat. This liquid is made up of half water and half antifreeze (commonly, ethylene glycol) which both keeps the water from freezing at low temperatures and raises its boiling point making heat transfer more efficient.

General Science

Cellular fermentation takes place:

anaerobically

If no oxygen is present, cellular respiration is anaerobic and will result in fermentation where either lactic acid or alcohol is used instead of oxygen.

Mechanical Comprehension

How much work can a 1 hp engine do in 3 seconds?

1650 ft⋅lb

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 1 hp \times 550 \frac{ft⋅lb}{s} \times 3s = 1650 ft⋅lb \)

Automotive Information

Coolant is circulated through the engine by the:

water pump

The water pump is driven by a belt connected to the crankshaft and ensures that coolant moves through the engine and radiator.

Automotive Information

Which engine stroke starts with the piston at top dead center?

intake stroke

The four-stroke piston cycle of internal combustion engines starts with the piston at top of the cylinder head (top dead center or TDC) during the intake stroke. The piston moves downward in the cylinder creating a vacuum that pulls an air-fuel mix into the combustion chamber through the now open intake valve.

General Science

The brain and spinal cord make up the __________ nervous system.

central

The nervous system consists of the brain and spinal cord (central nervous system) and the peripheral nervous system which is the network of nerve cells (neurons) that collect and distribute signals from the central nervous system throughout the body.

Automotive Information

A constant velocity (CV) joint is closely related to which of the following?

universal joint

Like CV joints, universal joints (U-joints) are located at each end of a drive shaft and allow the shaft to operate at a variable angle with the item it is driving. Universal joints perform the same basic function as CV joints but CV joints have a wider range of operation.