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Grade 7 Physical Science Review

STUDY
PLAY
Motion
the action of motion or being moved
Speed
Distance an object travels in a certain amount of time
Velocity
Speed in a direction
Vector
direction and magnitude of a force
Inertia
The tendency of an object to resist a change in motion
Momentum
quantity of motion of a moving object (mass x velocity)
Terminal Velocity
the highest speed a falling object can attain
Relative Motion
motion determined by the reference point or relative position that is chosen
Net Force
total force acting on an object
Unbalanced Force
forces that do not cancel each other out when acting together on a single object
Balanced Force
forces that cancel each other out when acting together on a single object
Gravity
the force of earth pulling things toward it's surface
Friction
a force that opposes the motion of one object moving past another
Acceleration
change in velocity over time
Slope
the steepness of a line
Mechanical Energy
The amount of work an object can do because of the object's kinetic and potential energies
Potential Energy
Energy that is stored
Kinetic Energy
Energy in motion
Conservation of energy
Matter is not created nor destroyed in any chemical or physical change
Thermal
Energy of heat
Nuclear
The potential energy stored in the nucleus of an atom
Work
Force multiplied by distance (W=fd)
Power
The rate at which work can be done
Joules
measurement of work
Watt
measurement of power
Electromagnetic energy
energy that is reflected or emitted in electric and magnetic waves
Chemical energy
A form of potential energy that is stored in chemical bonds between atoms
Heat
Energy due to temperature
Machine
something that uses mechanical power to perform a specific task
Lever
Simple machine made of a fulcrum, arm, load, and effort. Reduces the amount of force needed to do work
Pulley
A simple machine that helps lift a load higher while requiring the same amount of force
Wedge
A simple machine used to split a solid object with less force, made of two inclined planes
Screw
A simple machine that decreases the force needed to move an object, an inclined plane wrapped around a cylinder. (threads)
Fulcrum
The support on which a lever moves when it is used to lift something
Wheel and axle
A simple Machine used to reduce friction, and decrease the amount of force needed to do work
Inclined planer
A simple machine with a slanted surface that decreases the amount of force needed to move an object
Compound Machine
machine made of two simple machines
Mechanical Advantage
Efficiency of a machine to produce a small force, or effort, that can be applied to move a much greater resistance
Efficiency
measurement of the effectiveness of a machine to transform energy and power into force and movement
Force
a push or pull exerted by one object on another, causing a change in motion
Newton's 1st Law of Motion
an object at rest tends to stay at rest, a moving object tends to stay in motion
Newton's 2nd Law of Motion
an object moves in the direction of the force applied
Newton's 3rd Law of Motion
For every action there is an equal and opposite reaction