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Automotive Information

The two major types of vehicle braking systems are:

drum and disc

Brakes utlize friction to slow vehicle tires. Drum brakes employ a cast iron drum that roates with the vehicle axle. When hydraulic pressure is applied to the brake assemblies at the wheels, internal pistons expand and push brake shoes outward into contact with the brake drum slowing the rotation of the axle. More powerful disc brakes operate by pinching a rotating disc betweeen two brake pads and allow for a larger surface area to contact the disc, provide more force, and are more easily cooled.

Electronics Information

Using a fuse with a current rating higher than that required by a circuit:

makes the circuit less safe

A fuse is a type of low resistance resistor that stops current flow in a circuit in response to a larger than intended electric current flow. Using a fuse with a higher current rating than required by a circuit is less safe as it could potentially allow overcurrent and risk a fire or heat-related equipment damage.

Shop Information

Inside and outside micrometers measure inside and outside:

diameters

Micrometers measure the diameter of cylindrical objects. Outside micrometers measure the external diameter of cylinders and inside micrometers measure the internal diameter of the cylinder's hole.

Word Knowledge

Heidi's grandfather was gruff, barking stern orders and hardly smiling.

surly

Rough or stern in manner or speech.

Electronics Information

A transistor works by allowing a small amount of current to control general current flow. Where is the small amount of current applied?

base

The transistor is the foundation of modern electronic devices. It is made entirely from semiconductor material (making it a solid state device) and can serve many different functions in a circuit including acting as a switch, amplifier, or current regulator. A transistor works by allowing a small amount of current applied at the base to control general current flow from collector to emitter through the transistor.

Automotive Information

The wheel __________ is the mounting point for the wheel and tire assembly.

hub

The wheel hub is the mounting point for the wheel and tire assembly. The wheel hub can rotate while being held stable by the steering knuckle which applies the motion of the control arms to the wheels.

Electronics Information

The hertz is a unit of measurement for:

frequency

The hertz is a unit of measurement for frequency.

Mechanical Comprehension

If the green arrow in this diagram represents 420 ft⋅lb of work, how far will the box move if it weighs 140 pounds?

3 ft.

The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

W_in = W_out
F_effort x d_effort = F_resistance x d_resistance

In this problem, the effort work is 420 ft⋅lb and the resistance force is 140 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
420 ft⋅lb = 140 lbs. x d_resistance
d_resistance = \( \frac{420ft⋅lb}{140 lbs.} \) = 3 ft.

Mechanical Comprehension

A fixed pulley has a mechanical advantage of:

A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.

General Science

Which of the following is true about species groups?

a community is made up of a group of populations

A population is a group of organisms of the same species who live in the same area at the same time. A community is a group of populations living and interacting with each other in an area.