P1 Flashcards
How can energy be transferred?
By:
-Heating
-Waves
-Electrical currents
-A force acting upon something
What is a closed system?
An object or group of objects in which no energy transfers take place out of/into the energy stores of the system
What is the equation for work done?
W= F s, where s = distance
Name the force that opposes the motion of two surfaces in contact with each other:
Friction
What is the equation for elastic potential energy?
elastic potential energy = 0.5 × spring constant × (extension)^2, where spring constant is measured in N/m
When is an object described as elastic?
If it regains its original shape after being stretched or squashed
What happens to the work done on an elastic object if it is stretched/squashed?
It is stored as elastic potential energy
In terms of energy stores, what happens to a vehicle when it brakes?
-The kinetic store of the vehicle decreases
-The thermal stores of the brakes and the surroundings increase due to friction
How can machines be made more efficient?
-Lubrication to reduce friction
-Use of copper wires to minimise electrical resistance
How can energy be wasted in a machine?
Friction between moving parts, air and electrical resistance
List the different types of energy store:
Magnetic, thermal, kinetic, electrostatic, chemical, gravitational potential, elastic potential, nuclear
