Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/74

Click to flip

74 Cards in this Set

  • Front
  • Back

FORCE

A push or pull applied to an object that causes motion or a change in motion

FORCE

Mass x acceleration

Reaction force

Applied by an object's physical supports- keeps the object from moving in response to externally applied forces

Gravity

An external force

Center of gravity (COG)

The point in the body where the effect of the line of gravity is localized

Stress

Change in structure of a biological or non-biological material

1. Tension


2. Compression


3. Shear

Forces that cause stress

Tension

Forces pulling APART

Compression

Forces that act TOWARD each other

Shear

Parallel forces (Sliding across the surfaces)

Strain

Resultant deformation of stress (not necessarily permanent)

Pressure

Force per unit area

Pressure

Stress is directly related to....

Torque/moment

The product of the distance of the point of application of a force from the fulcrum and the magnitude of the force



(Magnitude x distance between application pint and fulcrum)

Fulcrum

Point of support

Lever arm

That which makes up the distance from a fulcrum to the point of application of a force

Torque

The longer the distance from the fulcrum, the greater the ___________ for the same force.

A body at rest tends to remain at rest and a body in motion in a straight line tends to remain in motion unless external forces act to change either of these states.

Newton's first law of motion

Inertia

What causes a person to be pitched forward in a wheelchair when it comes to a sudden stop.

Momentum

Mass X velocity

Velocity (speed)

Distance per unit of time

For every force of action, here is an equal but opposite force of reaction

Newton's third law

Direct current (battery powered devices- PWC)

Current which is constant due to a steady unchanging, unidirectional flow of charge

Voltage

A measure of the work required to move a unit charge from one point to another OR potential difference between 2 terminals

Volt

Unit of voltage

Resistance

The measure of the tendency of a material to impede the flow of electrons through it.

Low

Resistance is ______ in good conductors.

High

Resistance is _____ in poor conductors.

V=iR

Ohm's Law

The current flowing through the material

The voltage across conducting materials is directly proportional to______________.

Frequency (hertz)

Cycles per unit time

Kilohertz (KHz)

Sound frequency is measured in_________.

Applied outside force

The only thing that can change momentum

Amplitude

Maximum departure of the value of an alternating current or wave from the average value.

Power (watts)

Rate at which work is done.

Watts

Volts x amperes

Watt-hours

Rate at which power is being used

Cathode

Positive (+) terminal

Anode

Negative (-) terminal

Displacement

The position of the body in space

Translational movement

All parts of the body move in the same direction, at the same time, for the same distance

Rotational movement

Direction,distance, and time of movement occur simultaneously but moves through an angle around an axis or fulcrum

Static friction

The force that must be overcome to start a body in motion

Dynamic friction

Friction during movement (decreases once the body is in motion)

Current

The net charge crossing a cross section of a conductor per unit of time- charge in motion-flow of electrons past a given point

Amperes (i)

Unit of measurement for current

Alternating current (house current)

A current that reverses its direction at regular intervals

Larger

In American Wire Gauge, the smaller the number, the _______ the wire.

No. 14

The typical house wire is ______.

No. 12

The smallest wore permitted for wall outlets is _______.

16-20

___________gauge wire is typically used in battery operated devices.

Stranded wire

Smaller wires grouped together to make a larger, more flexible wire.

Heat

Current flowing through a wire causes_______.

Ultrasound

Sound waves that are too high in frequency to be heard by the human ear

Infrared

Signal sent by LED or laser diode

1. Good conductors of heat and electricity


2. Bright luster


3. Can undergo deformation without breaking (ductility)


4. High mechanical strength

Characteristics of metals

Iron

Most abundant metal on earth

Steel

An alloy of iron and carbon plus a small amount of other elements

Aluminum

Lightweight, non-ferrous metal with good electrical conductivity , corrosion resistance, good workability, and non magnetic

Copper

Corrosion resistant metal that had good strength and conducts better than all metals except silver

Magnesium

2/3 the weight of aluminum, high strength to weight ratio, corrosion resistant

Titanium

Advanced composite material composed mostly of carbon fiber

1. Easily fabricated


2. Lightweight


3. Corrosion resistant


4. Electrically resistant


5. Transparent and can be colored


6. Good damper

Advantages of plastic

voltage drop (wasted power)

Forcing too many amperes through a wire will cause a _______ ________.

1. Low strength


2. Dimensionally unstable


3. Thermally unstable


4. Deteriorates


5. Odorous


6. Difficult to repair


7. Costly

Disadvantages of plastics

Composites

Material that consists of elements and fibers in a matrix

larger

The _________ the wire, the lower the voltage drop.

Inefficiently

When there is a voltage drop, appliances work ___________ because the voltage at the beginning of he wire is higher than at the end causing it to work on a voltage lower than it was designed for.

Black and white; red

If a cable has 2 insulated wires, they are _______and_______. The 3rd is _______.

Hot, neutral

The black wire is always ______ and the white wire is _________ and connected to the ground at one point.

Uninsulated copper; green with yellow stripe

Ground wire is either _________ or _________ .

Fuse

A short piece of metal that melts when more than a predetermined amount of amperes flows through it.

Thermal or magnetic or both

Circuit breakers can be _______or_______.

Circuit breaker

Disconnects the load if it is overloaded