P1 Energy and Conservation Flashcards
(31 cards)
what is elastic potential?
the amount an object can be stretched while returning to its original form.
what is kinetic energy?
the rate at which objects move and their mass.
what is nuclear energy?
energy stored in the nuclei of an atom.
what is G.P.E?
the amount of energy at a certain height
what is thermal energy?
the total kinetic energy and potential energy that cause vibrations.
what is chemical energy?
the energy stored in chemical bonds
what is magnetic and electrostatic energy?
the store between repelling and attracting poles
what is the law of energy?
energy cannot be created or destroyed
what are the four energy transfers?
mechanical, electrical, heat and radiation
what is a closed system?
an object or group of objects in which no energy transfers can take place out or in the energy stores, only can be transferred to different stores within the system.
what is equivalent to work done?
energy transferred
what is the formula for work done?
work done (J)= force applied (J) x distance (m)
what opposes work done?
friction opposes work done, and is transferred into thermal energy
what is the formula for the change in G.P.E?
change in G.P.E (J) = mass (kg) x gravitational field strength (N/kg) x height (m)
what is the earth’s gravitational field strength?
9.8 N/kg
what is the formula for elastic potential?
elastic potential (J) = 1/2 x spring constant (N/m) x extension2 (m)
what happens to useful energy?
it’s transferred into the form wanted
what happens to wasted energy?
it’s not usefully transferred
what happens when energy is transferred into the surroundings?
it’s warmed up and dissipated
what happens if energy is dissipated further?
it becomes harder to use for further transfers, usually due to friction
what is input energy?
the energy supplied to a machine
how can energy be wasted?
friction, air resistance and electrical resistance meaning no machine can be fully efficient
how can machines be made more efficient?
using lubricant to reduce friction, making machines more streamlined and using copper wires
what is the formula efficiency?
efficiency = useful energy transferred/ total energy supplied x 100
