P1 Conservation and Dissipation of Energy Flashcards
Name the eight stores of energy
Chemical Kinetic Gravitational Potential Elastic Thermal Magnetic Electrostatic Nuclear
What is meant by the conservation of energy?
Energy can be transferred, wasted of dissipated, but energy cannot be created or destroyed. It remains the
same before and after the transfer.
What is a closed system?
An isolated system where no energy flows in or out of the system.
Give an example of an energy transfer
When an object is thrown upwards, the kinetic energy store decreases and the gravitational potential energy store increases
Friction when an object hits another object. For example a tire against pavement, creating sound and thermal energy.
What are the three ways energy can be transferred?
Heating
The use of forces
Electrically through an electric current
State the equation for kinetic energy
1/2 x mass (kg) x speed (m/s)2
E = 1/2mv2
State the equation for gravitational potential energy
1/2 x mass (kg) x gravitational field strength (n/kg) x height (m)
E = mgh
State the equation for elastic potential energy
1/2 x spring constant (n/m) x extension 2 (m2)
E = 1/2 ke 2
What is specific heat capacity?
Specific heat capacity is the thermal energy that must be transferred to change the temperature of 1kg of a material by 1 degree
How do you calculate the thermal energy required?
mass (kg) x specific heat capacity (J/kg degrees) x change in temperature (degrees)
What is power?
Power is the rate of doing work
What is power measured in?
Watts
What is the equation for power?
Energy transferred (J) / Time (s) P = E/T
What is the equation for the work done by a force?
W = Fs
What is the equation for change in electrical energy?
Q=It
