P1 Energy Flashcards
What is kinetic energy?
The energy store of moving objects
What is the formula for kinetic energy?
Kinetic energy = 0.5 x mass x (speed x speed)
What is elastic potential energy?
The energy stored in an elastic object when work is done on the object
What is Hooke’s law?
The extension of a spring is directly proportional to the force applied, as long as it’s limit of proportionality is not exceeded
What is a spring constant (k)?
Force per unit extension of a spring
what is gravitational potential energy?
the energy stored in an object due to its position above the earth’s surface.
This is due to the force of gravity acting on an object
What is the formula for gravitational potential energy?
GPE = m x g x h
what is specific heat capacity?
the amount of energy required to raise the temperature of 1 kg of a substance by 1 degree.
how many Joules are in 1 kilojoule?
1000 J = 1 kJ
what is the Law of Conservation of Energy?
energy can be stored, transferred usefully or dissipated but it cannot be created or destroyed
what is a system?
an object or group of objects
what happens to energy in a closed system?
no energy can enter or leave
what does friction cause?
energy to be transferred to thermal energy
how can you reduce unwanted energy trasfers?
you can reduce friction by:
using a lubricant
removing air particles around the system
when is work done?
whenever energy is transferred from one store to another.
what does mechanical work involve?
using a force to move an object
what does electrical work involve?
a current transferring energy
what is the formula for work done?
work done = force x distance
what is power?
the rate at which energy is transferred or work is done
what are the equations for power?
P = E/t or P = W/t
what is 1 watt?
1 Joule of energy per second
what is efficiency?
it tells the fraction of energy which is transferred to useful energy stores.
how can you increase the efficiency of a thermal energy transfer investigation with water?
use a lid
equipment made of plastic (material with lower thermal conductivity)
