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4.2 Energy is transferred when work is done. Tami Torres 2011. Some Helpful Definitions. Work ~ the use of force to move an object some distance. Joule ( jool ) ~ the standard unit of measure for work. One joule of work is done when a force of one Newton moves an object one meter.
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4.2 Energy is transferred when work is done. Tami Torres 2011
Some Helpful Definitions • Work ~ the use of force to move an object some distance. • Joule (jool) ~ the standard unit of measure for work. One joule of work is done when a force of one Newton moves an object one meter.
Work Transfers Energy • Energy ~ the ability of a person or an object to do work or to cause a change. • When you do work on an object, some of your energy is transferred to the object. • Think of work as the transfer of energy.
Kinetic Energy ~ the energy of motion. • Any moving object has kinetic energy. The faster it moves, the more kinetic energy it has. • Potential Energy ~ stored energy or energy due to its position or its shape. • A ball held in your hand above the ground has the potential to fall to the ground.
Mechanical Energy ~ the energy possessed by an object due to its motion or position. In other words, the combined potential and kinetic energy of an object. ME = PE + KE
Conservation of Energy ~ No matter how energy is transferred or transformed, all of the energy is still present somewhere in one form or another.
Conserving Mechanical Energy • At the top, a roller coaster has potential energy because gravity can pull it downward. There is no velocity so there is no kinetic energy. • As the roller coaster goes downhill, the potential energy decreases because the elevation decreases. The kinetic energy increases because the velocity increases. • At the bottom, all of the energy is kinetic because gravity cannot pull the roller coaster down any further. • The mechanical energy remains the same at all times.
Other Forms of Energy • Thermal Energy ~ the energy an object has due to the motion of its molecules. • Chemical Energy ~ the energy stored in chemical bonds that hold chemical compounds together.
Other Forms of Energy • Nuclear Energy ~ the potential energy stored in the nucleus of an atom. • Electromagnetic Energy ~ the energy associated with electrical and magnetic interactions. • It is possible to transfer, or convert, one energy form into one or more other forms.
