GCSE P1 Energy Equations and P2 Energy transfer by heating Flashcards
What is the principle of conservation of energy?
Energy cannot be created or destroyed. This means all systems do not lose energy.
Energy transferred is the same as…
Work done
Work done equation
Work done (J) = Force applied (N) x distance moved along the line of action of the force (m) W = F x s
Change in object’s Gravitational potential energy store equation
Weight (N) x change of height (m)
J = N m
Change of gravitational potential energy store (J)
GPE E = mass (kg) x gravitational field strength (N/kg) x change of height (m)
/\ E = m x g x /\h
Kinetic energy (J) equation
1/2 x mass(kg) x (speed)^2
1/2 x m x v^2
Elastic potential energy (J) equation
1/2 x spring constant(N/m) x (extension)^2
1/2 x k x e^2
Energy efficiency equation (%)
Useful output energy transferred by the device / total input energy supplied to the device
X 100
Power equation (W)
Energy transferred to appliance, E (Joules,J)/time taken for energy to be transferred, t (seconds,s)
Efficiency of Power %
Useful power out / total power in (x 100)
Energy transferred (Joules, J) equation
Mass, m (kilograms,kg) x specific heat capacity, c (J/kg°C) x temperature change (°C)
1.1 How do you show how energy is transfered?
You show this by showing a flow diagram
1.1 How can energy be transfered?
It is transfered by heating, waves, electric current or by a force when it moves an object.
1.1 What are all the fundamental energy stores?
Chemical energy stores, Kinetic energy stores, Gravitational potential energy stores, Elastic potential energy stores, thermal energy stores.
1.1 Show the chemical energy transfers in a battery
Chemical energy —-> Electrical energy —-> Light energy + Thermal energy
1.1 Show the energy transfer of an object falling
Gravitational potential energy –> kinetic energy –> thermal energy + sound energy
1.1 Chemical energy store Def
It includes fuels, foods, or the chemicals found in batteries
1.1 Kinetic energy Def
Describes the energy of an object moving
1.1 Gravitational Potential Energy DEF
Used to describe the energy stored in an object because of its position such as an object above the ground.
1.1 Elastic Potential Energy Store DEF
Describes the energy stored in a springy object when you stretch or squash it
1.1 Thermal Energy store DEF
The energy a substance due to temperature
1.2 Is energy an open or closed system?
It is a closed system because there would be no net change to the energy stored in system.
1.2 Describe the energy transfer of a bungee jumper
When the rope slacks, tightens and after it reaches the bottom
When the rope is slack: GPE energy store —> kinetic energy store
When the rope tightens: Kinetic energy store –> Elastic potential energy store (this gets bigger when the rope gets stretched)
After reaching the bottom: Elastic potential energy –> kinetic energy —> gravitational potential energy.
Doesn’t go back to original height