# Pre-Physics

Pre-Physics: Metrics, Motion, Newton's laws, energy, work, simple machines etc.

## Terms

undefined, object
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thermal energy
Total energy of a material's products, including PE and KE
liter
Base unit of volume for LIQUID
force
A push or pull one object exerts on another.
kinetic friction
Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together
SI
Modern version of metric system. Based on powers of 10.
balanced forces
forces that are equal in size and opposite in direction
elastic collision
objects collide and bounce off each other
graph
a visual display of information or data
temperature
a measure of the average KE of the particles that make up matter. More KE of particles=higher temp. Less KE= lower temp.
acceleration
The rate of change in velocity
speed
How fast something is going
inelastic collision
objects collide and stick together
centripal acceleration
Acceleration toward the center of a circle by an object moving along a circular path
work
The transfer of energy through motion. Measured in JOULES
derived unit
Unit of measurement obtained by combining SI units (density= mass/volume)
Newton's Second Law of Motion
An object's acceleration depends on its mass and the Fnet upon it.
centripal force
The force that causes an object moving along a circular path to move toward the center of the path
density
Describes how tighly packed a substance's molecules are.
second
The SI unit for time
heat
Thermal energy that flows from warmer material to a cooler material.
instantaneous speed
The rate of motion at a given instant in time (car speedometer)
resistance arm
The part of a lever that exerts the resistance force.
projectile
Any object shot of thrown through the air
ideal machine
A machine in which work input equals work output.
time
The interval between two events
air resistance
frictional force air exerts on a moving object. depends on shape, density, speed, and size
Newton's Third Law of Motion
For every action, there is an equal and opposite reaction.
velocity
the speed and direction of a moving object
machine
a device that makes work easier
volume
The amount of space occupied by an object.
mechanical energy
The total amount of KE and PE in a system
net force
The sum of the forces on an object when unbalanced forces are applied to it.
Newton's First Law of Motion
An object moving at a constant velocity keeps moving at that velocity unless an Fnet acts upon it.
inertia
The tendency of an object to resist any change in its motion
kelvin
The SI unit for temperature
screw
A simple machine consisting of a special type of inclined plane wrapped in a spiral around a cylindrical post
standard
In measurement, an exact quantity that everyone agrees upon.
kinetic energy
Energy in motion. The greater the mass and velocity, the greater the KE
wedge
a simple machine consisting of a moving inclined plane with one or two sloping sides. examples are knives and chisels.
specific heat
The amount of enegy needed to raise 1 kg of material 1 degree.
average speed
A rate of motion determined by= d/t
law of conservation of momentum
states that the total momentum of a group of objects is conserved unless a net force acts on the objects.
static friction
The force between two objects that are not moving relative to each other.
mass
The amount of matter in an object
potential energy
Stored energy.
simple machine
a device that accomplishes work with only one movement.
The number of times a machine multiplies the effort force applied to it.
constant speed
speed that does not change
inclined plane
A simple machine consisting of a ramp used to raise objects.
effort force
the force applied to a machine when a machine is used to do work.
energy
The ability to cause change.
meter
The SI base unit of length
effort arm
The part of a lever on which an effort force is applied.
resistance force
the force exerted by a machine to overcome resistance to gravity or friction.
fulcrum
The fixed point around which a lever pivots.
kilogram
The SI unit for mass
terminal velocity
the greatest velocity reached by a falling object. Occurs when force of gravity is balanced by air resistance
friction
The force that opposes motion between two surfaces that are touching each other
law of conservation of energy
a law stating that energy can form but can't be created nor destroyed under ordinary conditions
wheel and axle
A simple machine consisting of two different sized wheels that rotate together, such as a doorknob or wheel-handled faucet.
lever
a simple machine consisting of a bar that is free to rotate around a fixed point.
momentum
property of any moving object. product of mass and velocity
pulley
a simple machine consisting of a grooved wheel with a rope or a chain running along the groove.

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