Q&A Hero

Q: The bob of a simple pendulum is 0.50 m above the floor at its lowest position. Calculate the maximum speed of the bob when it is held at a maximum height of 2.5 m and released.

Q: A ball is dropped from an upper-story dorm window. Neglecting air resistance, what is the speed of the ball when it has fallen 2.5 m?

Q: A student weighing 700 N climbs a flight of stairs 5.0 m high in 10 s. What power was required?

Q: A student weighing 700 N climbs a flight of stairs 5.0 m high. Calculate the work done.

Q: A 0.10-kg ball is dropped from a height of 10 m and rebounds to a height of 8.0 m. a. Is energy conserved in the ball? b. If not, how much energy was lost, and what happened to it?

Q: A stone is dropped from a bridge 15 m above a river. With what speed does the stone hit the water?

Q: A force of 7.2 N acting on a 1.0-kg object initially at rest moves it through a parallel distance of 2.5 m. Neglecting friction, what is the speed of the object when it is moved 2.5 m?

Q: A force of 7.2 N acting on a 1.0-kg object initially at rest moves it through a parallel distance of 2.5 m. How much work is done on the object?

Q: Besides fossil fuels, the only other significant commercial sources of energy are ______________ and ______________.

Q: Energy sources that would be nonpolluting supplements to our energy are called ______________ fuels.

Q: The United States' most abundant fuel supply is ______________.

Q: The SI unit of power is the ______________.

Q: A watt is one ______________ per second.

Q: A 2-hp motor can do the same amount of work as a 1-hp motor in ______________ the time.

Q: A horsepower is a unit of power equal to 550 ______________.

Q: The time rate of doing work is called ______________.

Q: With a constant braking force, the stopping distance of a car is proportional to ______________.

Q: Gravitational potential energy is equal to the ______________ of an object times its height.

Q: A negative potential energy may be made positive by changing the _____________ point.

Q: The value of an object's gravitational potential energy depends on the ______________.

Q: When the height of an object is doubled, its gravitational potential energy is increased by a factor of ______________.

Q: When a moving object's velocity doubles, its kinetic energy increases by a factor of ______________.

Q: When the kinetic energy of a simple pendulum decreases, the ______________ of the pendulum increases.

Q: According to the law of conservation of energy, energy cannot be ______________ or ______________.

Q: The kilowatt-hour is a unit of ______________.

Q: In changing from one form to another, energy is always ______________.

Q: A system for which there are no outside effects is said to be ______________.

Q: Energy resulting from motion is called ______________.

Q: Kinetic and potential energies are forms of __________ energy.

Q: The sum of the kinetic energy and potential energy is called ______________ energy.

Q: The kinetic energy of a pendulum is ______________ at the bottom of its swing.

Q: The two types of mechanical energy are ______________ and ______________.

Q: In pushing an object on a level surface, work is done against ______________.

Q: In lifting an object, work is done against ______________.

Q: The units of work are the same as those of ______________.

Q: The product of one ______________ and one meter is one joule.

Q: The product of force times parallel distance is called ______________.

Q: Work is the process by which energy is ______________.

Q: The process by which electricity can be generated by using running or falling water is known as A) groundwater generation. B) hydroelectric generation. C) geothermal generation. D) steam generation.

Q: Energy provided directly from Earth's interior is called A) groundwater energy. B) geothermal energy. C) artesian energy. D) thermionic energy.

Q: Which of the following sources of energy presents the fewest pollution problems under normal operating conditions? A) Coal B) Natural gas C) Nuclear fission D) Hydroelectric power

Q: For which of the following reasons is production of ethanol unwise? A) Pollutants aren't significantly reduced. B) It takes twice as much fossil-fuel energy to produce ethanol than the ethanol that is produced supplies. C) It can drive costs of corn higher. D) All of the above.

Q: A mixture of ethanol and gasoline is called A) ethaline. B) gasanine. C) gasohol. D) gethanine.

Q: Some food costs may rise in the future as a consequence of the increased use of which food-based fuel? A) Ethanol B) Gasoline C) Oil D) Coal

Q: It is estimated that the global reserve of methane hydrate is ______________ the global reserves of coal, oil, and natural gas. A) equal to B) less than C) twice D) ten times

Q: One positive aspect of the potential use of methane hydrate as a fuel is that A) there is more of it than there is of coal, oil, and natural gas. B) it is easy to mine. C) its use will never contribute to global warming. D) it exists in a pure form ready for use.

Q: Which of the following is(are) drawbacks to the use of methane hydrate as a fuel? A) When melted, it produces methane, a greenhouse gas. B) It is difficult to mine as a solid located at the bottom of the oceans. C) It is mixed with water. D) All of these are drawbacks associated with methane hydrate.

Q: "Ice that burns" is better known as A) propane. B) frozen oil. C) coal. D) methane hydrate.

Q: Although the United States has less than 5% of the world's population, it accounts for approximately ______________ of the world's annual consumption of fossil fuels. A) 15% B) 25% C) 35% D) 45%

Q: Currently, in the United States, which sector of the economy uses the most energy? A) Industry B) Transportation C) Commercial D) Residential

Q: Currently, in the United States, which fuel is utilized to produce the majority of electrical power? A) Oil B) Natural gas C) Coal D) Nuclear

Q: Currently, in the United States, which fuel has the largest consumption? A) Oil B) Natural gas C) Coal D) Nuclear

Q: The largest reserve of energy in the United States is in what form? A) Oil B) Natural gas C) Coal D) Nuclear

Q: The average adult radiates heat energy at the same rate as A) a 10-W light bulb. B) a 100-kW light bulb. C) a 100-W light bulb. D) none of these.

Q: Which of the following is not a scalar quantity? A) Kinetic energy B) Potential energy C) Power D) Work E) None of these; that is, they are all scalar quantities.

Q: Which of the following is a unit of energy? A) kilowatt-hour B) newton C) joules per second D) newton-second E) none of these

Q: Which of the following is a unit of power? A) kilowatt-hour B) newton C) joules per second D) foot-pound E) none of these

Q: A kilowatt-hour is a unit that measures A) work per unit of time. B) energy. C) power. D) work time.

Q: What is bought from an electric company? A) Electrical energy B) Electric charge C) Electrical power D) None of these

Q: Which of the following is not a unit of power? A) ft lb/s B) kW h C) J/s D) watt

Q: Which of the following is not a unit of power? A) ft lb/s B) N m C) J/s D) watt

Q: One watt is equal to one joule per ______________. A) second B) newton C) hour D) kilogram

Q: One ______________ is equal to one joule per second. A) kilogram B) newton C) pound D) watt

Q: One watt is equal to ______________ per second. A) one kilogram B) one newton C) one joule D) one meter

Q: Power is A) the time rate of doing work. B) the time rate of doing velocity. C) the time rate of doing momentum. D) the time rate of doing force.

Q: Power is A) work divided by time. B) velocity multiplied by time. C) momentum divided by time. D) energy multiplied by time.

Q: A system may A) be isolated. B) have real boundaries. C) have imaginary boundaries. D) all of these

Q: Mechanical energy A) is the automobile energy. B) is the sum of kinetic and potential energies. C) is the kinetic energy. D) is the potential energy.

Q: Mechanical energy A) is always the total energy of a system. B) is the sum of the energies of motion and position. C) is always conserved. D) necessarily involves gravitational potential energy.

Q: The energy of a system A) always increases. B) always remains constant. C) increases when work is done by the system. D) increases when work is done on the system.

Q: The energy of a system A) always increases. B) always remains constant. C) decreases when work is done by the system. D) decreases when work is done on the system.

Q: We define the total mechanical energy of an object as A) potential energy plus kinetic energy. B) inertial energy plus kinetic energy. C) gravitational energy plus potential energy. D) mental energy plus physical energy.

Q: If you lift a 35-N weight vertically 50 m above the ground, you are A) doing work against gravity. B) doing work against friction. C) doing work against inertia. D) doing none of these.

Q: Potential-energy values may be A) positive only. B) negative only. C) zero only. D) all of these.

Q: The energy of position is called A) potential energy. B) power. C) kinetic energy. D) heat.

Q: Which of the following four objects has different kinetic energy? A) An object of mass m moving with speed 4v B) An object of mass 4m moving with speed 2v C) An object of mass 16m moving with speed v D) An object of mass 2m moving with speed 3v E) None of these; all four objects have the same kinetic energy.

Q: Which of the following four objects has the least kinetic energy? A) An object of mass m moving with speed 4v B) An object of mass 3m moving with speed 2v C) An object of mass 4m moving with speed v D) An object of mass 2m moving with speed 3v E) None of these; all four objects have the same kinetic energy.

Q: Which of the following four objects has the greatest kinetic energy? A) An object of mass m moving with speed 4v B) An object of mass 3m moving with speed 2v C) An object of mass 4m moving with speed v D) An object of mass 2m moving with speed 3v E) None of these; all four objects have the same kinetic energy.

Q: The potential energy of a pendulum is greatest A) when its potential energy is least. B) at the top of its swing. C) at the bottom of its swing. D) when its total energy is greatest.

Q: The kinetic energy of a pendulum is least A) when its potential energy is least. B) at the top of its swing. C) at the bottom of its swing. D) when its total energy is greatest.