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ch 4&5
Kinetic energy | energy of a moving object has because of its motion |
joule | SI unit of energy |
potential energy | stored energy an object has due to its position |
Elastic potential energy | energy stored when an object is compressed or stretched |
chemical potential energy | energy stored in chemical bonds |
gravitational potential energy | energy stored by objects due to their position above Earth's surface |
Mechanical energy | sum of the potential energy and kinetic energy in a system |
Law of conservation of energy | states that energy can never be created or destroyed |
Work | transfer of energy that occurs when a force makes an object move; measured in joules |
Power | amount of work done, or the amount of energy transferred, divided by the time required to do the work or transfer the energy; measured in watts |
Machine | device that makes doing work easier by increasing the force applied to an object, changing the direction of an applied force, or increasing the distance over which a force can be applied |
Input force | the force that is applied to the machine |
Output force | the force that is applied by the machine |
Mechanical advantage | ratio of the output force exerted by a machine to the input force applied to the machine |
Efficiency | ratio of the output work done by the machine to the input work done on the machine, expressed as a percentage |
Simple machine | machine that does work with only one movement |
Compound machine | machine that is a combination of two or more simple machines |