Glencoe Physical Science, Chapter 4

Explain the mechanical energy transformations for a swing. The ME is greatest initially.

As GPE is changed into KE, friction changes some of that total energy into TE. Eventually the person will cease to swing because there is no more NRG remaining as it slowly becomes TE.

Explain three forms of PE.

CPE- NRG stored in chemical bonds. GPE- NRG stored due to height. EPE- energy stored in a flexible, stretchy object.

Explain how work and energy are different.

Energy is the ability to cause change, performing work. Work is the act of applying a force, resulting in motion.

Explain how to calculate GPE.

Find the mass and the height. Multiply by 9.81.

Explain how to calculate KE.

Find the mass; square the speed. Multiply them both. Times by .5.

Explain how fossil fuels can release CPE energy in combustion.

Fossil fuels store the sun's NRG in chemical bonds. Combustion is a chemical reaction in which that CPE is changed into TE as the bonds are broken. The TE is used to generate electricity or to fuel an engine.

Explain why a rolling basketball eventually comes to a stop.

Friction converts kinetic energy to thermal energy, leaving zero mechanical energy in the system.

Explain how GPE & EPE are different.

GPE is a function of height, regardless of gravity. EPE is energy stored in a flexible, stretchy object.

Explain how GPE & CPE are different.

GPE is a function of height, resulting from gravity. CPE is energy stored in chemical bonds, regardless of height.

Explain how friction affects ME.

In any energy conversion, friction slowly converts ME into TE.

Explain how fruits store energy from the sun for humans to convert.

Light NRG comes from the sun & plants use it in photosynthesis, storing it in their chemical bonds. Then humans digest it, converting that CPE when they break the chemical bonds.

Explain how plants store and release energy as CPE.

Light NRG comes from the sun and plants use it in photosynthesis, storing it in their chemical bonds. Then humans digest it, converting that CPE when they break the chemical bonds.

Explain how a light bulb converts energy.

NRG enters a bulb as electrical NRG and the bulb converts it into light and thermal energy.

Explain how PE & KE are different.

PE involves stored energy, KE involves motion from converted PE.

Explain what is meant by power and how it is calculated.

Power is the rate at which NRG is converted. It is equal to the work divided by time. It is normally measured in watts.

Explain power and how it is calculated.

Power is the rate at which NRG is converted. Power = work/time.

Explain how proteins, carbohydrates, and fats are different.

Proteins and carbohydrates store 5 calories of NRG. Fats store about 9 calories of NRG.

Explain how ME is affected in the case of a roller coaster.

Some of the ME is changed into TE due to friction and is not available to be used again.

Explain how ME is affected in /any/ energy conversion.

Some of the NRG is changed into TE due to friction, leaving no ME in the end.

Explain how TE & ME are different.

TE is the result of friction. It is unintentionally taken from ME, not able to be used again. ME = KE + PE

Explain the analogy of how energy is like money.

The amount of money you have can be changed into something worth that same amount when you buy something. You can sell it the next day for the same amount, turning it into something else.

Explain what happens to the energy stored in plants when food is digested.

The energy from the sun is stored in chemical bonds. Breaking those bonds in a chemical change converts this energy.

Explain how the force of gravity affects GPE.

The higher up something is, the faster it will be going when it meets the bottom since it accelerates at 9.81 m/s/s due to gravity.

Explain what happens to the car's kinetic energy if a driver suddenly slams on the brakes of her car and skids to a halt.

The kinetic energy is transformed into thermal energy, heating the brakes, wheels, tires, and road.

Explain why the first hill of a roller coaster is generally the highest.

The roller coaster gains GPE by climbing the hill. It has essentially no kinetic energy at the top of this hill, so all its mechanical energy is stored as gravitational potential energy.