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Physical Science Chapter 3 Homework

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The quantity that has units kg * m2/s2 is known as a
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joule
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Coal that is used in a coal-fired power plant is
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ground to a face-powder consistency and blown into furnaces.
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The solar technology that is today contributing about as much energy as moving water is
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biomass
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Of the following, which rank of coal has the most desirable burning properties and highest energy content?
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bituminous
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The potential energy of a ball on the ground is zero. If the ball is now in the bottom of a hole, its potential energy is
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negative.
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Two students stand poised to leap off a high dive structure into the swimming pool below. Student B is twice as massive as student A. Which of the following is true?
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Student B did twice as much work climbing to the top of the structure.
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Roughly, what fraction of our nation’s current energy needs is supplied by coal?
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20%
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The amount of energy produced by power-generating dams is
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decreasing, as more energy is used but new dams are not being built.
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Your electric bill for 1500 kilowatt-hours is a charge for the power you have used that month.
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False
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Which form of energy does not require matter for traveling through space?
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radiant
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Which one of the following does not have the same units as the others?
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momentum
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A car traveling 20 mph can stop in about 40 ft. If the same car were traveling twice as fast, its stopping distance would be roughly
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160 ft.
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When you throw a ball into the air, its kinetic energy
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all of these.
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Energy sources used today are mostly in what form of energy?
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chemical
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You do more work on yourself when you run up the stairs than when you walk slowly.
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False
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Plants convert radiant energy from the Sun into chemical energy by a process called photosynthesis.
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True
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As we deplete our coal reserves, we can replace this lost source of energy by increasing our output of hydroelectric power.
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False
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You can find the kinetic energy of a book of a certain mass just before it hits the floor after falling a certain distance by using which equation?
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PE=mgh
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The increase in potential energy caused by lifting an object can be calculated by multiplying its weight by its change in height.
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True
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Kinetic energy refers to
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energy of motion.
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Which one of the following has an appropriate unit?
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All of these.
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Work is the rate at which you expend energy.
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False
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The watt (W) is a unit of
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power.
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While exploring an ancient Mayan tomb, you discover that the walls are closing in on you. By exerting 400 N of force, you are able to keep the wall from coming closer. The work you are doing on the wall is
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zero, because the wall is not moving.
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Energy is not conserved when a moving object slows to a stop.
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False
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Nearly all of the energy consumed today is provided by petroleum, coal, hydropower and nuclear sources.
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True
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Which solar technology makes economic sense for a homeowner?
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water heating
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When a light bulb is rated at 60 W, it means that
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each second, the bulb converts 60 J of electrical energy to heat and light.
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The energy an object has because of its position is called potential energy.
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True
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An object that falls twice as far will be moving twice as fast when it hits the ground.
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False