energy stores and systems Flashcards
what happens when energy is transferred to an object?
the energy is stored in one of the objects energy stores
what are the 8 different energy stores?
thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic and nuclear
what happens when a system changes?
energy is transferred
what are closed systems?
when neither matter nor energy can enter or leave, the net charge is always zero
how is energy transferred when boiling a kettle?
water is heated by kettles electrical energy into the water’s thermal energy store
what is work done?
energy transferred
who is doing the work when throwing a ball?
initial force exerted by the person throwing it
what is a objects kinetic energy store?
its movement
if an object has greater mass and speed what will it mean?
the more energy in its kinetic energy store
what is the formula for kinetic energy?
kinetic energy = 1/2 x mass x volume^2
example: a car of mass 2500 kg is travelling at 20 m/s, what is its kinetic energy store
1/2 x 2500 x 20^2 = 500 000 J
what is gravitational potential energy?
raised objects
the higher the objects lifted means what amount of energy is transferred?
more energy is transferred
how do you work out the change in gravitational potential energy?
change in energy = mass x gravitational field strength x height
example: if an object has a mass of 2 kg and a gravitational strength of 40 n/kg, what is the change in energy if its put at a the top of a 3m shelf?
2 x 40 x 3 = 240 J
