1. Energy Flashcards
What are the nine types of energy?
Kinetic, sound, light, thermal, electrical, gravitational potential, elastic potential (strain), chemical, nuclear
What are the two ways that energy can be transferred?
From place to place or from one form into another
What is ‘waste energy’?
Energy that is converted to either the wrong place or the wrong form
What is ‘useful energy’?
The energy converted to where it is wanted in the form wanted
What is an efficient device?
A device where most of the energy is usefully converted
What form is waste energy nearly always in?
Heat and sound energy dissipated to the surroundings
What is a closed system?
A system where the total energy is always the same. No energy is transferred in or out.
Equation for efficiency?
Useful energy given out by device / energy put in x100
What is work done equal to?
Energy transferred
Equation for work done?
Work done = force x distance in direction of force
What is the rate at which energy is transformed?
Power
When is work done?
When any object is moved around ie energy is supplied
Equation for power?
Power = energy / time taken
What is 1 watt equal to?
1 Joule per second
What do you pay for when you pay for electricity?
The energy transferred
Equation for kinetic energy?
Ek=1/2mv²
Equation for gravitational potential energy?
Ep=mgh
How to calculate weight?
Mass x gravitational field strength
How to calculate a change in kinetic energy?
Ek=1/2mv²-1/2mu²
What is change in kinetic energy equal to?
Work done and kinetic energy transferred
Equation for elastic potential energy?
Ee=1/2ke²
Why does a compression still act like an extension?
The same amount of energy is stored
What is internal energy?
The energy stored by the particles of a substance
What is internal energy a sum of?
The kinetic energy of all the particles and the potential energy of all the particles due to their relative positions and forces between them