7.9 World Energy Use

All bodily functions need energy and oxygen.

The many small muscle actions accompanying all quiet activity, from sleeping to head scratching, ultimately become thermal energy, as do less visible muscle actions by the heart, lungs, and digestive tract.
It's a response to low body temperature that pits muscles against one another to produce thermal energy in the body.
The biggest surprise is that 25% of the energy the body consumes is used to maintain electrical potentials in all living cells.
Some of the bioelectrical energy can be used to power chemical processes in the body, such as fat production.

The vision center of the brain has an increased level of energy consumption.

The patient was being asked to identify faces.

Energy is an important part of society.

Access to adequate and reliable energy resources is important for economic growth and for maintaining the quality of our lives, because we live in a very interdependent world.
Current levels of energy consumption and production are not sustainable.
Roughly 40% of the world's energy comes from oil.
Oil prices are dependent on new discoveries and political events around the world.

Natural gas and solar contributions are increasing, but the fuel mix is still dominated by oil.

It will not be easy to shift to non-fossil fuels because of the link between global warming and fossil fuel use.

In the developing countries, world energy consumption has increased.

In the past 50 years, global demand for energy has tripled.
Many of the developed countries, especially those in Europe, are hoping to meet their energy needs by expanding the use of renewable sources, because much of this growth will come from the rapidly booming economies of China and India.
Wind energy is growing very fast, even though it is only a small percentage.
Germany plans to have 20% of its electricity and 10% of its energy needs come from renewable resources by 2020.
The rapid economic growth of China and India is being hampered by the lack of energy.
In 2003 China overtook Japan as the world's second largest consumer of oil.
Coal dominates the commercial energy resources of China, accounting for 1/3 of its energy consumption.
The United States was the largest generator in 2009.
Coal and wood are the main energy resources in India.
Half of India's oil is imported.
70% of India's electricity is generated by coal.
Significant strides are being made in renewable energy.
India has the largest solar cooking program in the world and a rapidly growing wind energy base.

Some of the prime energy users in the world are shown in Table 7.6.

Some countries get a lot of their electricity from renewable resources.
New Zealand's electricity demand is met by hydroelectricity.
Roughly 10% of the U.S. electricity is generated by renewable resources.
The percentages in this table are blank because it is difficult to determine total contributions of renewable energy in some countries.

Economic well-being is dependent upon energy use, and in most countries higher standards of living are matched by higher levels of energy consumption per capita.

This dependency will be changed by increased efficiency of energy use.
There is a global problem of balancing energy resource development against harmful effects on the environment.

There has been an increase in energy usage.

There are some differences between two terms in the area of energy use that need to be drawn out.
The "law of the conserve of energy" is a very useful principle in analyzing physical processes.
It is a statement that can't be proven from basic principles, but is a very good bookkeeping device, and no exceptions have ever been found.
The total amount of energy in an isolated system will never change.
The important philosophy of energy saving is very different from the principle.
Reducing the amount of energy used by an individual or group through reduced activities such as turning down thermostats, driving fewer kilometers, and increasing conversion efficiency is what this concept is about.

Since energy in an isolated system is not destroyed or created, one might wonder why we need to be concerned about our energy resources.

The final result of most energy transformations is waste heat transfer to the environment and no longer useful for doing work.
The potential for energy to produce useful work has been degraded in the energy transformation.

If the force and displacement are the same and the object is displaced, the work is positive.

The magnitude of the displacement and the angle between them are measured.

The net work is the work done by the net force and the SI unit for work and energy is the joule.

Work done on an object transfers energy.

If the displacement is zero, the work done by a force is zero.

The work-energy theorem states that the net work calculate motion in terms of the known potential on a system changes its energy and work done.

The potential energy can be from the net force or directly apply the laws.

The law ofConservation of Energy states that the total is always the same in any process.

The acceleration may change due to gravity.

Earth's surface is due to its position in the mass-Earth.

The physical significance of the differences in energy is written in the equation form.

It is not possible to convert all the energy of a system to work.

A conservative force is one for which work depends only on the starting and ending points of a motion.

We can define potential energy for any 7.7 Power conservative force.

The average power for work done over a is the spring's force constant and is the displacement time.

The watt (W) is the SI unit for power.

When only conservative forces act on and within a system, the total mechanical energy is constant.

This is stored in fat.

The rate at which the body uses food energy to sustain 7.5 Nonconservative Forces life and to do different activities is called the metabolic rate, and the corresponding rate when at rest is called.

Friction is an example of a nonconservative force that splits mechanical energy into thermal energy in the body.

About 75% of food calories are used to sustain basic or equivalent body functions.

The relative use of different fuels to provide energy has been matched by higher levels of energy consumption per changed over the years, but fuel use is currently capita.

In your speed of 5 m/s downhill, is energy transferred or changed in form?

Explain how this is accomplished without having an initial speed of 5 m/s uphill, and it coasted doing work.

When you lift a book onto a time it doesn't work.

The force that a diving board exerts is conservative.

If the potential energy of a diving board is negligible, describe changes in the potential energy of a diving board as a swimmer dives from it, starting just before the swimmer steps on the board until just after his feet leave it.

Energy is put into a system by work done on it.

An example for each statement can be given.

The following scenario should be considered.

A car with less joules.

There is a stop at a gas station.

Discuss the effectiveness of diet and exercise when the javelin is stuck into losing weight, noting that most athletic activities the ground after being thrown.

The single cup of yogurt can contain 1360 kJ if devices have an efficiency of less than one.

There are four different forms of energy.

An example of a conversion from each of these forms to regular exercise may increase the metabolism.

The majority of electrical appliances are rated in kilowatts.

A car can travel108 km at a speed of 30.0 m/s and use 2.0 gal of gasoline.

How much work does a supermarket checkout attendant do by pushing a can of soup with a constant speed and force?

The work is done to accomplish this task.

Suppose the ski patrol lowers a rescue sled and victim, crate 4.00 m up along a ramp that makes an angle of having a total mass of 90.0 kg, down a slope at with the horizontal.

The force coefficients of 500 N on the crate parallel to the ramp and moves of the sled and the snow is 0.

How much work is done by the sled as it moves through a crate and up a ramp.

A man pushes a crate.

The acts on the wagon show how much work is done by the boy and his sister.

A rescue sled is lowered down a steep slope.

The child and Energy Theorem are shown.

A shopper pushes a grocery cart 20.0 m at a constant speed of 110 km/h against a 35.0 N frictional force, while an 80.0-kWh space shuttle is in motion.

He was moving at 27,500 km/h.

Use energy metabolism rates to find the force the shopper exerts.

You need to know the definition of a nautical mile.

The Pyramid of Cheops has a mass that is about shock because it absorbs force over a long distance.

The force of a blow is lessened by padded gloves.

The force exerted by an identical blow in the coaster that had descended 20.0 m was only slightly days when no gloves were used and the knuckle was greater than the face.

The force with glove on is implied by this.
Even though the ratio is lower, confirm this statement by taking enough damage to cause it.

A toy car is moving.

In a downhill ski race, the advantage is not gained by getting a running start.

To demonstrate this, find the final speed and time taken for a skier who skies 70.0 m along a slope.
Discuss the benefits of getting a running start in a very competitive event.

A subway train is stopped by a large spring bumper at the end of its track.

There are thousands of nuclear bombs, follow the steps in the Problem-Solving Strategies for and their energy can be trapped in underground Energy.

A skier with an initial speed of 12.0 m/s may be realized in the next century.

She has a relatively clean and almost unlimited supply of final speed at the top.
The snow has a 0.0800 friction between it and her skis.

The approximate factor by which the power output of this object has used in coasting to the top of a rise is calculated from Table 7.3.

Imagine a star 1000 times brighter than our Sun hitting the water with a speed of 24.8 m/s independent emitting 1000 times the power.

The average brightness of the observable galaxies is less than our own.

An airplane with useful power for several hours at a stretch, perhaps by engines that produce 100 MW of power to reach a speed pedaling a mechanism that drives an electric generator.

You can show how you follow the steps in power.

How much is the air problem-solving strategies for energy?

How long will it take this person to get the maximum power?

The speed of 10,000 kg is increased.

A shot-putter who takes 1.20 s to jump from some height to the ground creates very large forces in the joints.

Large forces in the feet and legs are caused by jogging on hard surfaces.

You might think her efficiency is 20%.

Santorini, Greece, on April 23, 1988, in the Daedalus 88, converted the chemical energy of body fat into an aircraft powered by a bicycle-type drive mechanism.

The data from Table 7.5 can be used to calculate the kilojoules he metabolized during the flight.

The arms have a low efficiency in this activity, so shoveling snow can be very taxing.

The Great Pyramid of Cheops was built with an arm that was 80.0 N.

Historians estimate that 20,000 workers spent 20 years constructing it.

If there were 1000 mountain climbers, they would carry bottled oxygen.

Simple machines were used to build ancient pyramids.

Discuss if exercise is enough to cause a person to lose weight.

A car ad claims that it has a car that's 900 lbs.

Assume all values are known to three significant figures.

There are forces doing push-ups.

The metabolism of the body fat is 9.30 kcal/g when the intake of calories is less than needed.

You center of gravity is claimed by the manufacturers of an exercise bicycle.

The Integrated Concepts are on their machine.

Find his power output for work at the rate of 0.500 kg per hour.

A person is climbing and descending stairs.

The same person can descend stairs at a 80.0 N backward with his arms at a 1.80 m long faster rate for a nearly unlimited time in spite of the fact stroke.

Consider humans generating electricity by pedaling a speed.

A toy gun uses a spring with a force constant of 300 N/m it would take to replace a large electrical generation to propel a steel ball.

If the facility is compressed.

A basketball player crouches down while waiting to jump.

After he exerts a force on the floor, his feet leave the floor and his center of gravity is above its normal standing erect position.