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44 Cards in this Set
- Front
- Back
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Earth has a lot of _____, so it pulls all objects towards its ____ with a lot of force. *****
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mass center
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Earth's___attracts objects near its surface, pulling them towards its _______.
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gravity center
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Gravity pulls the apple and the feather downward. Their speed _______ as they fall. Both fall at the same rate in a vacuum why?
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increases because there is no air in the vacuum
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The moon has less ____ than the Earth. So the moon pulls objects where with less/more* what? ***********
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mass to the center of it with less gravitanional force.
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______ is the measurment of gravitanional force acting on an object.
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weight
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The earth has more mass and, therefor, more what then the moon?
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gravitanional force
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Even tought he ______ _____ changes ont the moon, the ____ of an astronaut doesn't change.
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gravitanional force mass
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on the moon, object weigh about _-_ of what they weigh in earth.
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one sixth
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The what is by a force feild called a what?
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magnet magnetic field
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A magnet has two ends called what?
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poles
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The pulling force of a magnet is _____ at the what?
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strongest at the poles
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When a bar magnet moves freely its what always points north, and its what always points south.
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north-seeking-pole south-seeking-pole
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a magnets poles are often markes what?
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N and S
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magnets both ____ each other, and _____ each other or push away each other. These forces get what as the poles get ____ together.
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attract or repel stronger closer
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unlike poles ____. Like poles ____.
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attract and repel
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balanced force are...
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forces that act on an object but cancel out each other.
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unbalanced forces are..
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forces that act on on a object and don't cancel out each other; unbalanced forces cause a change in motion.
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net force is...
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the combination of all the forces acting on a object
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bouyant force is...
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the upward force exerted on an object by water.
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unbalanced forces may make an object ___, ___ __, ____ ___, _____, or _____ __ _______.
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start, speed up, slow down, stop, or change direction.
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Net force affects an objects what?
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motion
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When forces are ______ the net force is zero.
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balanced becuse if they are not moving the object has no net force.
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The net force on an object isn't zero when the forces are _________, or when ___ ___.
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unbalanced or when motion changes.
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Whan wrestlers push in oppisite direction with unequal streanths, a change in ____ results.
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motion
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Forces pushing or pulling to the right are given ___ values. Forces pushing to the left are given ___ values. - - - - - - - - - - - - - - -
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positive neigitive
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__________ _______ it the reason water pushes up on objects.
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bouyant force
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work is...
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the use of a force to move an object through a distance
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simple machine is...
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a device that makes taskes eaiser by changing the size or direction of a force or the distance over which the force acts.
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a lever is..
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a bar that makes it eaiser to move things
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a fulcrim is..
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the balancced point on a lever that supports the arm but does not move.
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wheel-and-axle
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a wheel with a rod or axle in the center
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a inclined plane is
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a ramp or another sloping surface
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the only way to do work is to make sominthing what?
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move
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work is a product of two things, ___ and ______.
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force and distance
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work depends of ____. But ___ matters too.
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sistance but force
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work is meauseres in units called what? *****
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joules
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How do machines make work easier? ******
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they make work easier by reducing the amount of force people must use to do the work.
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Levers have two parts, the ____ , moves. The other part is the balanced point or the _____.*****
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lever arm fulcrum
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a Wheel-and-axle helps you open a ____. ****
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door
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The wedge is made up of two ______s that form a cutting edge. a ____ and a ____ are both wedges. an __ is a wedge used to chop wood. ******
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inclided planes nife and a chisel ax
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Compond machines are made up of what?
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simple machines
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A push lawn mower is a compond machine. it uses a __ to cut the grass, this is attached to the _____, and the handel of the mower is a ___. ******
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wedge whee-and-axle lever
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sailors often use compond machines called what?
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block and tackle.
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1000N + (- 50N)=
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50N net force = one force pulling in one direction - the force pulling in the oppisite
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