21 terms

Forces and Motion Ch 15 Test

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Motion
A change of position. Moving from one place to another.
Distance
How far it is from one location to another
Speed
The distance an object moves in a certain period of time
Force
Any kind of push or pull
Gravity
is a force that pulls two objects together.
Weight
is a measure of the force of gravity on an object.
Three things affect the motion of an object
strength and direction of the force, mass of object
The strength of the force example
roll a ball gently, it moves slow ;throw a ball hard it moves faster, farther
The direction of the force
push an object to the right it moves right. Pull an object up it moves up
The mass of the object
The smaller the mass of an object, the easier it is to move.
You must apply a force
to make an object move.
An object will keep __________ until another force stops it.
moving
Net Force
The sum of all the forces on an object
If two horses pull a wagon equally , the net force is _______________ the amount of one horse
twice
If there are two children with one toy, and one is pushing the toy while the other is pulling the same toy with the same amount of force, than the net force is
zero
Friction
is one force that stops things or slows them down.
Most rough surfaces make _________ friction than slow surfaces.
more
You can slide ___________ on ice than on dirt or grass.
further
Gravity
is a force that pulls two objects together.
Earth has a _________________ gravitational pull.
strong
If you throw a ball into the air it ____________ back down because of the Earth's pull on it
falls