Flashcards in P1 Conservation of energy Deck (12):
How can energy be transferred?
Energy can be transferred by heating, by waves, by an electric current, or by a force when it moves an object.
What are the changes in energy stores that happen when an object falls?
When an object falls and gains speed, its store of gravitational potential energy decreases and its kinetic energy store increases.
What is the conservation of energy?
Energy cannot be created or destroyed but can be changed.
Why is the conservation of energy a very important idea?
Because it applies to all energy changes.
What is a closed system?
A closed system is a system in which no energy transfers take place out of or into the energy stores of the system.
How do you describe the changes to energy stores in a closed system?
Energy can be transferred between energy stores within a closed system. The total energy of the system is always the same, before and after, any such transfers.
What is energy transferred equal to?
Energy transferred = work done
How do you work out work done?
Work done, w (joules,j) = force applied, f (newtons, N) x distance moved along the line of action of the force, s (metres, m)
What does work mean in science?
In science, work is done on an object when a force makes the object move.
What happens to work done to overcome friction?
Work done to overcome friction is transferred as energy to thermal energy stores of the objects that rub together and to the surroundings.
What is the kinetic energy equation?
Kinetic energy (joules, J) = 1/2 x mass (kilograms, kg) x speed (v2)