Energy changes in a system + conservation Flashcards
Give 4 ways in which energy is transferred by
1) heating
2) waves
3) electric current
4) by a force when it moves an object
Give the energy transfer of a bowling ball hitting the ground
Kinetic energy transferred (by heating) to thermal energy store of object and its surroundings
Give 3 things that can be done with energy
It can be:
. Transferred usefully
. Stored
. Dissipated
Define closed system
Object(s) where no energy transfers go into or out of
Give an example of a closed system
Falling object: gravitational decreases as kinetic increases
When is work done on an object
When a force is applied to it and energy is transferred to the object
Work is done to move an object, what 2 values are equal
Energy supplied and work done
When is no work done on an object
When a force is applied to it and it doesn’t move
What is the correlation between work done by gravity on an object and decrease in gravitational potential energy
They are equal
When is an object described as being elastic
If it regains original shape after being stretched or squashed
What happens when an elastic object is stretched/squashed
Work is done on it and is stored as elastic potential energy
What is potential energy and an example
1) energy held by an object based on its position, stresses within itself, electrical charge etc.
2) heavy ball of a demolition machine is storing gravitational potential energy when it is raised
How does one calculate elastic potential energy
0.5 x extension^2 x spring constant
How do you calculate an energy transfer from gravitational potential energy to kinetic
How would one calculate the amount of energy stored in/released from a system AS its temperature changes
Energy = SHC x mass x temp change
