p1 Flashcards
name the eight energy stores
- kinetic
- thermal
- gravitational potential
- magnetic
- elastic
- chemical
- electrostatic
- nuclear
what is meant by a system?
- an object or a group of objects
when a system changes - what happens?
- energy is transferred
what is a closed system?
- when energy or matter cannot enter or leave
how is energy transferred when throwing a ball in the air?
chemical to kinetic
how is energy transferred when dropping a ball?
gravitational to kinetic
how is energy transferred when a car breaks?
kinetic to thermal
how is energy transferred during a collision between a moving and stationary object?
kinetic to elastic and thermal
what is specific heat capacity?
- the amount of energy required to raise the temperature of 1kg of the substance by 1 degrees
what is the conservation of energy principle?
- energy can be transferred, stored or dissipated but it cannot be created or destroyed.
what is meant by dissipated energy?
- energy that is wasted or lost during a reaction
what is power?
- the rate at which energy is transferred (work done).
what is the unit of power?
- watts
name the two equations used to calculate power
- power = energy transferred/time
- power = work done/time
describe the energy transfer in the pendulum (the weight hung)
- when the ball goes up, it has maximum gravitational energy.
- when it goes to the bottom, it has maximum kinetic energy.
- energy is transferred to gravitational energy to kinetic back to gravitational energy.
- how can lubrication reduce frictional forces?
- a thin layer is formed so two surfaces don’t rub against each other.
what is conduction?
- how thermal energy travels through solids.
what is convection?
- when particles with lots of heat energy replace particles with less heat energy.
how can you reduce heat loss in a house?
- cavity walls
- the air gap reduces the amount of energy lost
- reduces energy transfer by convection - double-glazed windows
- they trap the heat
- they have an air gap between two glasses, which prevents energy transfer by conduction. - loft insulation
- reduces convection currents