25 terms

# Science - Forces and Motion

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Force
A push or pull from one object to another
Examples of forces
gravity, friction, magnetism, air resistance, pushing, pulling
Gravity
A force that pulls all objects together.
Objects
These all have gravity.
The more mass an object has
Its' gravity increases.
As distance between objects increases
Gravity decreases
The less mass an object has
Its' gravity decreases.
As distance between objects decreases
Gravity increases
Friction
A force between two objects where one object works to slow down or stop the motion of the other object.
Rubbing hands together
Example of friction
Smooth surfaces
These have less friction than rough surfaces
Ice or glass
Example of surfaces with low amounts of friction.
Grass or gravel
Example of surfaces with high amounts of friction.
Rough surfaces
These have more friction than smooth surfaces
Air resistance
This is caused by air hitting an object and slowing it down.
Drag
This is the effect of air resistance.
Why parachutes work
They slow people down falling to the ground because of air resistance.
Flat sheet of paper
This falls to the ground slower than crumpled paper because of air resistance.
Newton's First Law
An object at rest remains at rest and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force
Newton's Third Law
for every action, there is an equal and opposite reaction (action/reaction forces)
Forces always happen in these
pairs
Action/Reaction
These foces are always equal and in opposite directions. Newton's Third Law of Physics.
Ball and bat - why does ball fly
The mass of the bat is greater.
Floor and foot - which is the action force
Foot
Floor and foot - which is the reaction force
Floor