P1-Energy Stores and Systems Flashcards
(21 cards)
Name all the energy stores
Thermal Kinetic Gravitational Potential Elastic Potential Chemical Magnetic Electrostatic Nuclear
How is energy transferred?
Mechanically by doing work Electrically work done by moving charges Heating Radiation Between energy stores
What is a system?
A single or group of objects that you are interested in
What happens when a system changes?
Energy is transferred into or away from he system, between two objects or between types of energy store
What is a closed system?
A system where neither matter nor energy can enter or leave
What is the net change in a closed system?
The net change in the total energy of a closed system is always 0
Describe the energy transfer of boiling a kettle
Energy is transferred to the water (from kettle heating element) by heating electrically into the waters thermal energy store
What is work done?
Work done is another way saying energy transferred. It can be done when current flows or by force moving an object
What happens when you throw a ball upward
Initial force is exerted by a person and causes work to be done, energy is transferred from the chemical store in a persons arm to the kinetic energy of the ball and arm
What happens when a ball is dropped
The gravity does the work
Causes energy to be transferred from the balls gravitational energy store to its kinetic energy store
What happens when a car brakes
Friction between the wheels and the brakes does work as it slows down
It causes energy transfer from the wheels’ kinetic energy stores to the thermal energy store of the surroundings
Which store does eventually all energy end up in?
Thermal Store
What way can energy use to be transferred
Sound waves
If anything is moving what energy store is the energy in?
Kinetic
What is the equation for working out kinetic energy
Kinetic Energy (joules)=
1/2 x mass (kg) x speed (m/s) squared
If a car of a mass of 2500KG is travelling at 20 m/s calculate the kinetic energy
1/2 x 2500 x 20 x 20
(20 squared)
=500 000 joules
When you lift an object work is done, where store does the energy worked go into?
When an object is lifted energy always goes into the gravitational potential energy store
What is the equation for the gravitational potential energy
GPE=
Mass x height x gravitational field strength
What happens when an object falls
Energy from the gravitational potential energy store is transferred to its kinetic energy store if there’s no air resistance. But if there is then some of the energy will also go into the thermal energy store (like in real life)
What store is filled if an object is stretched or squashed
The elastic potential energy store
What is the equation for the elastic potential energy store as long as the limit of proportionality has not been exceeded
Elastic potential energy=
1/2 x spring constant (N/m) x extension ^2
