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96 Cards in this Set
- Front
- Back
The motion of an object looks differnernt to observers in different...
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frames of reference
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The direction and length of a straight line from the starting point to the ending point of an object's motion is...
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displacement
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the SI unit for measuring _______ is meter.
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distance
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Displacement and velocity and examples of ________ because they have both magnitude and direction.
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vectors
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The sum of two or more vectors is called the...
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resultant vectors.
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Speed is measured in units of...
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meters per second.
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A car's speedometer measures...
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instant speed.
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v=D/t is the equation that defines...
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average speed.
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A constant slope on a distane-time graph indicates ________ speed.
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constant
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The difference between speed and velocity is that velocity indicates the ________ of motion and speed doesn't
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speed
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A distance-time graph indicates an object moves 20 km in 2 h. The average speed of the object is ______ km/h
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10
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Because its __________ is always changing, an object moving in a circular path experiences a constant change in velocity.
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direction
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Two or more velocities add by _________________
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vector addition
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A moving object does not ________ if its velocity remains constant
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acceleration
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Freely falling objects accelerate at 9.6 m/s squared because the force of_____________ acts on them
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gravity
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The velocity of an object moving in a striaght line changes at a constant rate when the object is expierencing constant___________
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acceleration
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The acceleration of a moving object is calculated by diiding the change in _______ by the time which change occurs
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speed or velocity
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Accelerated motion is represtented by a(an) ________ line on a distance-time graph
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curved
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A car that incrases its speed from 20 km/h to 100 km/h undergoes _________ acceleration
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postive
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___________ is how fast a velocity is changing at a specific time
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instantaneous speed
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A push or pull is an example of a(an)_________
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force
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The type of force measured by a grocery store spring scale is__________
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weight
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The sum of all the forced acting on an object is called the ____________
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netforce
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If the forced acting on an object produce a net force of zero, the forces are called __________
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balenced forces
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The force that oppeses the motion of objects that touch as they move pass each other is called ___________
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friction
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It usally takes more force to start an object sliding than it does to keep an object sliding because static frictin is usally ________ than sliding friction
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greater
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The two forces acting on a falling object are gravity and ________
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air resistance
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The path of motion of a thrown javelin is a example of
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projectile
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The tendency of an object to resist any change in its motion is called
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inertia
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During a head on auto collision____________ causes a passenger in the front seat to countinue moving _________
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inertia, forword
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The acceleration of an object is equal to the net _____ acting on the object divided by the objects ________
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force, mass
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The force of gravity acting on an object is the object's...
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weight
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If a golf ball and bowling ball are rolling at the same speed, the _______ ball has greater momentum
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bowling
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When you push on a wall, the ________ pushes back on you.
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wall
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In a closed system, the loss of momentum of one object ________ the gain in momentum of another object
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equals
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The observation that a charged object can attract or repel other charged objects led scientists to conclude that there are ____ types of charges
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two
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The universal force that is the most effective over the longest distances is...
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gravity
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The centripal force acting on the moon continuously changes the ___________ of the mooon's motion.
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direction
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Pressure is the result of force distributed over an...
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area
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The formula, Force/Area, is used to calculate...
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pressure
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The SI unit of pressure is the...
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pascal
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A pascal, the SI unit of pressure, is equal to 1 newton per...
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square meter
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A substance that flows and assumes the shape of its container is a...
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fluid
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As a liquid is added to a beacker, the pressure exerted by the liquid on the bottom of the beacker...
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increases
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The pressure exerted by a fluid at any given depth is exerted _________ in all directions.
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equally
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As your altitude increases, air pressure...
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decreases
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A hydraulic jack is an application of _______ principle
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Pascal's
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A device that uses pressurized fluids acting on pistons of defferent sizes to change a force is called a...
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hydrolic system
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As the speed of a fluid increases, the _______ within the fluid decreases
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pressure
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In a hydrolic lift system, the fluid pressure exerted throughout the system is
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constant
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The downward force produced when air flows over the winglike spoiler on a race car is an example of _____________ principle
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Bournouli's
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The apparent loss of weight of an object in a fluid is called ________
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bouancy
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The direction of the buoyant force on an object placed in a fluid is
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upward
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Even a rock at the bottom of a lake has a ____________ force acting upward.
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bouyant
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The unit g/cm3 is often used to express _______
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density
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As you climb a high mountain, the buoyant force exerted on you by the atmosphere _________
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decreases
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A submerged submarine alters its __________ to rise or fall in the water.
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density
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The weight of an object that sinks in a fluid is _________ greater than the buoyant force acting on it.
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greater
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For work to be done on an object, the object has to __________
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move
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Any part of a force that does not act in the direction of an object's motion does no ________ on an object.
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work
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The SI unit of work is
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joules
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You calculate work by multiplying the force acting in the direction of _______ by the distance the object moves.
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motion
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The rate at which work is done is called
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power
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The SI unit of power is
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watt
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The watt and the horsepower are both units of
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power
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A machine is a device that changes a
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force
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A device that changes the size or direction of force used to do work is called a
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machine
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The force that is exerted on a machine is called the ________ force
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input
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Besides a reduction in friction, the only way to increase the amount of work output of a machine is to ________ the work input
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increase
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The ________________ of a machine is the number of times that the machine increases the input force.
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mechanical advantage
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The mechanical efficiency of any machine is always _______ than 100 percent
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less
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A _________ can be described as an inclined plane wrapped around a cylinder
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screw
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The fulcrum is always between the effort force and the resistance force in a ________-class lever
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first
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The ideal mechanical advantage of a third-class lever is always ________ than 1
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less
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As the thickness of a wedge of given length increses, its IMA
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decreases
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Two or more simple machines working together make up a __________ machine
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compound
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A watch consists of a complex systems of gears. Each gear acts as a continuous
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lever
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Energy of an object increses when ____________ is done on the object
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work
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Energy and work are measured in the SI unitcalled the
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joule
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If the ________ of an object doubles, its kinetic energy doubles
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mass
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The kinetic energy of an object is propotional to the sqare of its
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speed
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Energy that is stored due to position or shape is called _________ energy
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potential
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When a pole-vaulter flexes the pole, the pole-vaulter increases the pole's __________ potential energy
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elastic
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You can calculate an object's gravitational potential energy by using the equation
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potential energy = mass x acceleration of gravity x height
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Mechanical energy does not include kinetic energy of ______ energy
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chemical
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The sum of the kinetic energy and potential energy of an object is called its _______ energy
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mechanical
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All energy can be considered as kinetic energy, _________ energy or the energy in fields.
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potential
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Wind turbines comvert ________ energy into electrical energy
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kinetic
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the process of changing energy from one form to another is called energy _____________
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conversion
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"Energy cannot be created or destroyed" is a statement from the law of
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conservation of energy and mass
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When an apple falls from a tree to the ground, the apple's beginning kinetic energy and ending gravitational potential energy are both equal to
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0(zero) joules
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In the equation E = mc2, c is the speed of
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light
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Energy resources that exist in limited amounts and, onece used, cannot be replaced except over the course of millions of years are called ___________ energy resources
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non-renewable
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Flat collector plates through which water flows are found in ___________ solar energy systems
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active
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Geothermal energy, in addition to being renewable, offers the benefit of being
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non-polluting
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Turning off unused lights or appliances is an example of energy
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conservation
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