p1 Flashcards
Define energy
The ability for something to do work.
Define conservation of energy
Can’t be created or destroyed. It can transfer between stores.
Give the unit of energy
Joules (J).
Name the 7 different energy stores
Chemical, gravitational, kinetic, nuclear, thermal, electromagnetic, elastic
Identify which store of energy is associated with objects raised above the earth’s surface
Gravitational.
Identify which store of energy is associated with hot objects
Thermal.
Identify which store of energy is associated with moving objects
Kinetic.
Identify which store of energy is associated with objects that have been stretched
Elastic.
Identify which store of energy is associated with the nucleus of an atom
Nuclear.
Identify which store of energy is associated with the energy stored in bonds between atoms
Chemical.
Identify which store of energy is associated with charged or magnetised objects
Electromagnetic.
Give the equation for calculating weight
Weight = mass x gravity
Give the equation for calculating work done
Work done = force x distance
Give the equation for calculating Kinetic Energy
Kinetic energy = 0.5 x mass x speed²
Give the equation for calculating Gravitational Potential Energy
Gravitational potential energy = mass x gravity x change in height
Give the equation for calculating force applied to a spring
Force applied = spring constant x extension
Give the equation for calculating efficiency of energy or power
Efficiency = useful output (energy or power) / total input (energy or power)
Define efficiency
A measure of the useful energy transferred by an object compared to the total amount of energy it uses.
Describe how the efficiency of a machine can be improved
Lubricate moving parts to reduce friction. Secure all screws to reduce vibrations. Use streamline shapes.
Give the equations for calculating power
Power = work done / time; Power = energy transferred / time
Define power
The amount of energy transferred by an object each second.
Give the unit of power
Watts (W).
