Year 9 Energy Flashcards
(40 cards)
What is energy ?
Energy is the ability to do work
Name eight energy stores
Chemical, kinetic, gpe, thermal, elastic potential, magnetic, electrostatic, nuclear
What are three types of fossil fuels ?
Coal, oil and gas
What must you always have when writing an energy transfer ?
An arrow and at least one energy on each side
Why can efficiency never be 100% ?
There is always wasted energy
Why can’t you have an efficiency of over 100% ?
As stated in the law of conservation of energy you can’t create energy
What is the calculation to find efficiency?
Useful energy/ total energy
How many n/kg is gravity ?
10n/kg
What is power ?
The rate of transferring energy or doing energy
What is power measured in ?
Watts
How do you calculate the power ?
Energy/time or work/time
What is in the law of conservation of energy?
Cannot create energy, cannot destroy energy and can transfer between stores
What is energy measured in ?
Joules
What is drag ?
It’s the type of friction in the air
Are energy transfers efficient or inefficient ?
Inefficient
What does balance forces mean ?
Constant speed
How do you calculate work ?
Force x distance moved in direction of force
What happens to the kinetic energy you have as you speed up ?
You get more kinetic energy
How do you calculate the gain in gravitational potential ?
Ep = mgh
How do you calculate velocity?
V = square root (2Ek/m)
How do you calculate power ?
P = E/T
How do you calculate energy ?
E = PT
How do you calculate time ?
T = e/p
How do you calculate mass ?
M = Ep/gh
