GHSGT Physics Review

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GHSGT Physics Review
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Motion

• One possible unit of speed is ___.
• a. miles per hour
• b. kilometers per hour
• c. light years per century
• d. all of the above
• e. none of the above

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The answer is D.

• Average Speed is a distance traveled divided
• by the time required for the trip.
• a. speed distance / time
• b. velocity distance / time in a direction
• c. An acceptable unit would be any measure
• of length over any unit of time.
• d. mi/hr, km/hr, and m/s are common units for
  
• speed or velocity.

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Motion

• Acceleration is defined as the change in ___.
• a. distance divided by the time interval
• b. velocity divided by the time interval
• c. time it takes to move from one speed to
• another speed
• d. time it takes to move from one place to
• another place
• e. velocity of an object

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The answer is B.

• Acceleration is the change in velocity divided
• by the time it took to change the velocity.
• a. acceleration ? velocity / ? time
• b. Acceleration tells how fast an object is
• getting faster (or slower).
• c. Acceleration also tells if an object is
• changing direction.
• d. The units for acceleration are a distance
• over a time squared (i. e. m/s2).

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Motion

• Suppose you take a trip that covers 240 km
• in 4 hours. Your average speed is ___.
• a. 960 km/hr
• b. 480 km/hr
• c. 240 km/hr
• d. 120 km/hr
• e. 60 km/hr

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The answer is E.

• Speed distance / time
• Speed 240 km / 4 hr
• Speed 60 km/hr

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Newtons Laws

• A sheet of paper can be withdrawn from
• under a carton of milk without toppling it if
• the paper is pulled quickly. The reason this
• can be done is that ___.
• a. The milk carton has very little weight.
• b. There is an action/reaction pair operating.
• c. Gravity pulls very hard on the milk carton.
• d. The milk carton has inertia.
• e. none of the above

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The answer is D.

• Newtons first law states that an object tends
• to retain its current state of motion unless
  acted
• on by a net force. This is the law of inertia.
• a. More massive objects have more inertia
• because they are better at resisting
• changes in motion.
• b. There was not enough friction to move the
• milk carton with the paper.

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Newtons Laws

• Compared to its weight on the earth, a 10 kg
• object on the moon will weigh ___.
• a. less
• b. more
• c. the same amount

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The answer is A.

• Weight is the force that an object experiences
• due to gravity. An objects weight changes
• depending upon where it is (i. e. on the earth,
• on the moon, or on Mars).
• a. The units for any force are Newtons.
• Mass is the amount of stuff in an object. An
• objects mass never changes no matter where
• its located.
• a. measured in kilograms.

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Newtons Laws

• Newtons second law states that force is
• proportional to both mass and acceleration
• (F m a).
• a. The acceleration due to gravity on the
• moon is less than that on earth, therefore
• the object will have a smaller weight.
• b. mass and weight are often confused. An
• object will have the same mass (amount
• of stuff) on both the earth and the
  moon.

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Newtons Laws

• Newtons third law states that, for every action,
  
• there is an equal and opposite reaction.
• a. Forces always act in pairs. For example, if
• you kick a football, your foot applies a
  force
• to the football. However, the football
• applies an equal and opposite force to
  your
• foot.

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Newtons Laws

• Friction ___.
• a. acts in a direction that opposes the motion
• of an object.
• b. comes from microscopic bumps that act as
• obstructions to the objects motion.
• c. is the name given to the force acting
• between surfaces sliding between one
• another.
• d. all of the above
• e. none of the above

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The answer is D.

• Friction is the force that exists between
• contacting objects moving past one another.
• a. It is caused by interactions between the
• objects on a microscopic scale, as in the
• diagram below.
• b. Friction on an object is always opposite the
• direction of the objects motion.
• c. The units for friction, as for any
• force, are Newtons.

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Momentum

• Which has more momentum, a large truck
• moving at 30 miles per hour or a small truck
• moving at 30 miles per hour?
• a. the large truck
• b. the small truck
• c. Both trucks have the same momentum.

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The answer is A.

• The momentum of an object is the product of an
  objects mass and velocity.
• a. Momentum (p) (mass) (velocity)
• b. The units of momentum are kg m/s.
• c. Since the trucks have the same velocity,
• the one with the larger mass has the
  larger
• momentum.

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Momentum

• A 4 kg ball has a momentum of 12 kg m/s. What
• is the balls speed?
• a. 3 m/s
• b. 4 m/s
• c. 12 m/s
• d. 48 m/s
• e. none of the above

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The answer is A.

• p (m) (v)
• v p / m
• v 12 kg m/s / 4 kg
• v 3 m/s

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Work

• If Harry pushes an object with twice the force
• for twice the distance, he does ___.
• a. the same work
• b. twice the work
• c. four times the work
• d. eight times the work

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The answer is C.

• Work is the force times the distance over which
• the force acts.
• a. Work (force) (distance)
• b. The units for work are Joules.
• b. Since there was 2 times as much force and
• 2 times as much distance.
• c. W (2F) (2d)
• d. W 4 (F) (d)
• e. The amount of work he did increased by a
• factor of 4.

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Power

• If Lydia pushes a red box that weighs 10 N for 5
• m across a room in 10 seconds, and she
• pushes a blue box that weighs 10 N for 5 m
• across the same room in 5 seconds, with which
• box did she use more power?
• a. the red box
• b. the blue box
• c. She expended the same amount of power
• for both boxes.

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The answer is B

• Power is the work applied divided by the
• amount of time it took to perform the work.
• a. The units for power are Watts.
• b. Power work / time
• c. Power (10 N) (5 m) / 5 s
• Power 10 Watts for the blue box (B)
• d. Power (10 N) (5 m) / 10 s
• Power 5 Watts for the red box

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Energy

• As a pendulum swings back and forth ___.
• a. Potential energy is transformed into kinetic
• energy.
• b. Kinetic energy is transformed into potential
• energy.
• c. At the lowest part of the swing, its energy
  is
• all kinetic.
• d. At the end points of the swing, its energy is
  
• all potential.
• e. all of the above

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The Answer is E

• Kinetic energy is energy of motion.
• Potential energy is stored energy or energy of
• position.
• a. The pendulum is at rest at the top of its
• swing. It has no kinetic energy, but much
• gravitational potential energy.
• b. The units for work, kinetic
• energy and potential
• energy are Joules.

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The answer is E.

• b. At the bottom of its swing, it has no
• potential energy because the potential
• energy has been converted to kinetic
• energy. (it is moving fast!)

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Simple Machines

• The ratio of output force to input force in a
• simple machine is called the ___.
• a. fulcrum
• b. pivot point
• c. efficiency
• d. mechanical advantage
• e. lever arm

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The answer is D.

• Mechanical advantage (MA) tells you how much
• a machine multiplies the force you apply.
• a. MA output force / input force
• b. Nothing is free! The trade-off is that you
• apply a small force over a large distance
  to
• apply a large output force over a small
• distance. Think about a wrench or a ramp.
• c. The amount of work (force times distance)
• remains relatively constant with any loss
• due to friction.

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Heat Transfer

• Heat transfer by conduction occurs when ___.
• a. Electrons bump into atoms and other
• electrons.
• b. Large numbers of atoms move from place
• to place.
• c. Atoms give off heat in the form of
• electromagnetic waves.
• d. Electromagnetic waves travel from one
• place to another through a vacuum.
• e. none of the above

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The answer is A

• Conduction is the transfer of energy as
• particles and molecules collide with each other.
• To do this, the objects have to touch.

conduction
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Heat Transfer

• Heat transfer by convection occurs when ___.
• a. Electrons bump into other electrons.
• b. Large numbers of atoms move from place
• to place.
• c. Atoms give off heat in the form of
• electromagnetic waves.
• d. Electromagnetic waves travel from one
• place to another through a vacuum.
• e. none of the above

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The answer is B.

• Convection is the bulk movement of heated or
• cooled material within a sample, as in warm air
• rising and cool air sinking.

convection currents in boiling water
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Heat Transfer

• Heat travels from the sun to the earth by ___.
• a. conduction
• b. convection
• c. radiation
• d. insulation
• e. vacuumization

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The answer is C.

• Electromagnetic radiation is emitted by the sun,
• some of which encounters the earth, adding
• energy to the matter of the earth.
• a. Radiation is the transfer of energy by the
• emitting of electromagnetic radiation
  which
• is then absorbed by another object.

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Phase Changes

• Evaporation occurs when matter changes from
• a ___.
• a. gas to a solid, b. gas to a liquid
• c. solid to a liquid, d. solid to a gas
• e. liquid to a gas
• Condensation occurs when matter changes
• from a ___.
• a. gas to a solid, b. gas to a liquid
• c. solid to a liquid, d. solid to a gas
• e. liquid to a gas

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The answers are E then B.

• A phase change is accompanied by the
• absorption or the release of energy.
• a. A diagram for water with common phase
• change terms is provided below.

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Waves

• The distance between successive identical
• parts of a wave is called its ___.
• a. frequency
• b. period
• c. wavelength
• d. velocity
• e. amplitude

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The answer is C.

• Wavelength is the distance from crest to crest
• or trough to trough, measured in meters.
• Amplitude is the size of the disturbance, from
• center to peak or center to trough.
• Frequency is how many time the disturbance
• occurs per unit time, typically in cycles per
• second or Hertz (Hz).

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Waves

• Sound waves cannot travel in ___.
• a. air
• b. water
• c. steel
• d. a vacuum
• e. Sound can travel in all of the above.

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The answer is D.

• Sound is a mechanical wave. It requires a
• medium, or matter, to travel through.
• Electromagnetic waves do not need a medium
• to travel through. Electromagnetic waves from
• the sun travel to the earth through the near-
• vacuum that is outer space.

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Waves

• If the sun were to disappear right now, we
• wouldnt know about it for about 8 minutes
• because it takes 8 minutes ___.
• a. for the sun to disappear
• b. to operate receiving equipment in the dark
• c. for light to travel from the sun to the earth
• d. all of the above
• e. none of the above

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The answer is C.

• Waves travel at a certain speed. Wavelength
• and frequency are related to speed.
• a. Wave speed (frequency) (wavelength)
• b. Electromagnetic radiation travels at the
• speed of light (c) which is 3 x 108 m/s or
  
• 186,000 miles per second. The sun is
• so far away that it takes almost 8 minutes
  
• for these waves to reach the earth.
• c. Mechanical wave speed depends on the
• matter it is traveling in. Sound is
  faster in
• solids than liquids and slowest in gases.

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Light

• Different colors of light correspond to different
  
• light ___.
• a. velocities
• b. intensities
• c. polarities
• d. frequencies
• e. none of the above

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The answer is D.

• Our eyes interpret the frequency of light waves
• as color.
• Because frequency is related to wavelength by
• speed, another acceptable answer could be
• wavelength. However, this was not one of the
• choices.

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Light and Color

• Complimentary colors are two colors that ___.
• a. look good together
• b. are primary colors
• c. are next to each other on the color chart
• d. produce white light when added together
• e. none of the above

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The answer is D.

• Lights primary colors are red, green, and
• blue.
• a. Red and green light make yellow light.
• b. Blue and red light make magenta light.
• c. Blue and green light make cyan light.
• d. Red, green, and blue light combine to make
  white light.

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Light and Color

• d. Hence, a primary light color and its
  complementary color will create white light.
• e. Light colors opposite each other on the
• wheel here produce white light.

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Electric Charge

• Two like charges ___.
• a. attract each other
• b. repel each other
• c. neutralize each other
• d. have no effect on each other
• e. must be neutrons

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The answer is B.

• Charges that have the same sign (negative /
• negative or positive / positive) will repel each
• other whereas charges that have opposite signs
• (negative / positive) will attract each other.

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Electricity

• A 10 O resistor has a 5 A current running
• through it. What is the voltage across the
• resistor?
• a. 5 V
• b. 10 V
• c. 15 V
• d. 20 V
• e. more than 20 V

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The answer is E.

• Ohms Law states that voltage (current)
• (resistance)
• a. Voltage I R
• b. I is the symbol for current. Current is
• measured in amps (A).
• c. R is the symbol for resistance. Resistance
• is measured in Ohms (O)
• d. V I R V (5 A)(10 O) V 50 Volts

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Electricity

• To form an electric circuit, you need ___.
• a. a power source
• b. some resistance (i. e. a light bulb)
• c. wires or conductors to connect everything
• d. a complete path for the current
• e. all of the above

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The answer is E.

• A complete circuit needs a voltage source (like
• a battery), wires to connect all of the
• components, and a load to consume the energy
• (such as a light bulb or your IPOD).

source (battery)
load (resistor)
_
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Electric Circuits

• The total resistance of a 3 O resistor and a 6 O
• resistor in series is ___.
• a. 18 O
• b. 9 O
• c. 6 O
• d. 3 O
• e. 2 O

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The answer is B.

• For resistors in series, add the resistances
• together to determine total resistance.
• For resistors in parallel, add the inverses of
  each
• resistor to get the inverse of the total
  resistance.
• This problem involved a series
• circuit.
• Rtotal R1 R2Rtotal 3 ohms 6 ohmsRtotal
  9 ohms

series parallel
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Electric Circuits

• Equation for adding the resistors in a series
• circuit.
• Rtotal R1 R2 R3 . . . .
• Equation for adding the resistors in a parallel
• circuit.

1 R1
1 R2
1 R3
1 Rtotal
. . . . .



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End of GHSGT Physics Review