Chapter 1 - Energy Flashcards
(19 cards)
What is potential energy?
Potential energy is the energy stored inside an object.
What do you call the type of potential energy when a spring is stretched?
Elastic potential energy.
When water is stored behind a dam also stores potential energy. What is it called?
What does it stands for?
Gravitational Potential energy
GPE
What is Energy measured in?
Joules.
J
What is the formula of weight?
W=m*g
Weight= mass * gravity
What is the formula for Elastic potential energy
E= 0.5*Ke2
What is kinetic energy?
It’s the energy transfer to make an object move.
What is the formula for Ke
Ke=0.5mv2
What is Work done?
What is its measurement?
It’s the work done when a force acts on an object and the object moves along the line of action of force.
Joules
What is the equation of Work done (Wd)?
Wd= f*d (distance moved along the line of action of force)
What is power?
It’s the rate at which energy is transferred or the rate at which work is done; an energy transfer of 1 J/s is equal to a power of 1W
What is the formula for Power?
What is the measurement for Power?
P= Wd/t
Power= Work done / time
Watts (W)
What is specific heat capacity?
What’s its symbol?
Unit?
It’s the energy needed to raise the temperature of 1Kg of a substance by 1 ºC
“C”
J/Kg
What is the Specific Heat Capacity for water at 1 Kg
Water= 4200 J/Kg ºC
What is the formula for Specific heat capacity?
ΔE=mc Δ ØºC
How to reduce energy transfer?
Lubrication= oiling up the parts of the machine or lubricating them, reduces the friction force. So less energy is wasted.
Or
Thermal insulation= surrounding a hot object with insulating material, or thermal insulation, reduces the rate at which energy is transferred away from it so the hot object cools down slowly. Clothing made out of wool is a good conductor. Air is trapped between the wool fibres. Wool in air are bad conductors of thermal energy.
What is dissipation?
Dissipation is the spreading out of energy into the environment, so that its stored in less useful ways.
What is efficiency?
Efficiency is the useful output energy divided by the total input energy transfer.
What is the formula for Efficiency?
Efficiency= useful energy output/total energy input
