P1 Flashcards
what is a closed system
energy can be transferred between energy stores in a closed system but the net energy of the system doesn’t change
what is work done
the same as energy transferred
how do you calculate work done on an object when it cuases displacement
work done = force applied x distance moved by object
joules) (newtons) (metres
what is weight in newtons equivalent to
mass x gravitational field strength as weight is a force
what is the kinetic energy equation
1/2 x mass x velocity^2
what is the elastic potential energy equation
1/2 x spring constant( N/m) x extension^2
what happens as energy disspiates
it gets less and less useful
how does friction waste energy and how can it be reduced
friction causes energy to be transferred to thermal energy. This can be reduced by lubricating to reduce friction
how does wire resistance waste energy and how can it be reduced
resistance of a wire casues it to heat up when current passes through it. This can be reduced by using wires with little resistance
how can you reduce air resistance to make energy transfers more efficient
streamline objects to make them more aerodynamic
how does sound created by machinery waste energy and how can it be reduced
when machinery vibrates etc energy is wasted as sound energy. This can be reduced by tightening loose parts etc
what is the wasted power equation
total power in - useful power out
