9.4 Energy Change Flashcards
(19 cards)
What is kinetic energy?
Energy of a moving object.
What happens to kinetic energy when mass doubles?
Kinetic energy doubles
What happens to kinetic energy when speed doubles?
Kinetic energy quadruples
What is potential energy?
Energy an object has because of its position or structure
What are the four types of potential energy?
Nuclear, gravitational, elastic, chemical
What are the four types of kinetic energy?
Heat, sound, light, electrical, mechanical (mechanical doesn’t need to be known)
What is an alternative name for potential energy?
Stored energy
What causes an object to have gravitational potential energy?
If it’s above the ground
What causes an object to have elastic potential energy?
If it’s a stretched or compressed spring
How does elastic potential energy become kinetic?
When it is released and returns to its original shape
What is the law of conservation of energy?
An object may be transferred or transformed, but never created or destroyed.
True or false: There is energy loss or gain during an equation
False
Energy involved in the systems is the same.
What does a flow diagram show/draw one.
One arrow coming in with a label of energy, multiple arrows coming out, their length relative to how much energy is in that form. Some (normally one) is useful energy, the rest is waste energy.
Alternatively, it is the name of energy, an arrow going into more. All the useful energy is in one bracket labelled, while the waste energy is in another bracket labelled.
What is the formula for energy efficiency?
[Useful output ( J ) divided by energy input ( J )] multiplied by 100.
Gives an answer in %.
What is the kinetic energy formula in words and mathematically?
Words - Kinetic energy = 1/2 mass x speed^2.
Mathematically - Ek = 1/2mv^2
What is the speed foruma (using kinetic energy and mass)?
sqrt(2 times Ek divided by m)
What is the mass foruma (using kinetic energy and speed)?
(2 times Ek) divided by v^2
What is the GPE (gravitational potential energy) formula?
Words - GPE = Mass x Acceleration due to gravity (9.8 on Earth) x height
Mathematically - Ep = mgh
What are all the measurements in for the GPE (gravitational potential energy) formula in?
Ep = J (Joules)
Mass = kg
Gravitational field strength = 9.8 N/kg (Earth)
Height = m
