# GRADING CRITERIA WORK, ENERGY, POWER by 96FdgP

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```									                   GRADING CRITERIA WORK, ENERGY, POWER

G-level:
A work is done when an object moves a distance (in the direction of force).
Work done= force x distance moved. The unit for work and energy is joule (J) or Nm.

If an object is hauled (släpas) along a bed (underlag) , the force of friction (friktionskraften)
tries to stop the movement. The greater friction , the greater the work to move an object a
certain distance.

The higher an object moves, the greater potential energy (lägesenergi) it gets.

The greater speed and mass , the greater its kinetic energy (rörelseenergi).

Potential energy can change to kinetic energy and vice versa.

Energy is stored work.

The law of conservation of energy (Energiprincipen): Energy can change from one type to
another , but it cannot be made or destroyed.

When energy is changed you always get heat energy .

Levers (hävstänger) and inclined planes (lutande plan) are examples of machines. A machine
is anything which makes forces more convenient to use.

The golden rule of mechanics (Mekanikens gyllene regel) : What you gain in force, you loose
in distance.

The power (effect) is how much work is done during a certain time, usually 1 second. Power
is measured in watts (W ; 1W=1Nm/s).

Efficiency (verkningsgraden) is how much of the power input that becomes power output (hur
stor del av den tillförda energin som lämnas I form av nyttig energi). It is usually given in %.

VG-level:

Calculate work , effect and efficiency.

MVG-level:

Advanced calculations of work, effect and efficiency.

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