PHYSICS PAPER 1

Created by

Sahana.s

Cards (50)

energy is never created or destroyed only transferred
energy stores: thermal (heat)
energy stores: kinetic (moving)
energy stores: gravitational potential (height)
energy stores: elastic potential (strech)
energy stores: chemical (body)
energy stores: magnetic (attraction)
energy stores: electrostatic (electrons)
energy stores: nuclear (boom)
Mechanical work done: force needed to move an object
Electrical work done: energy required to overcome the resistance of the wires in the circuit
kinetic energy: 1/2 mv^2
kinetic energy : energy possessed due to motion
kinetic energy: depends on speed and mass ( faster objects have more kinetic energy) (heavier objects have more kinetic energy)
Gravity: force of attraction between two objects
GPE: Mass x gravitational field strength x height
gravitational field ( influence of gravity around an object)
if an object interacts with a gravitational field it experiences a force creating a force of attraction (weight)
Weight = Mass x Gravitational field strength
conservation of energy : energy cant be created of destroyed but can be transferred, stored or dissipated
open system —> energy and matter can freely move in the environment vs environment (outside the system)
closed system energy and matter cant enter or leave the system
heat is transferred by conduction (solids), convection (fluids: liquids and gases) or radiation ( empty space )
Conduction: vibrating particles transfer energy to neighboring particles
thermal conductivity : metals have a high thermal conductivity as plastics and fluids have a low thermal conductivity
thermal conductivity: how well objects can transfer thermal energy through conduction
convection: particles move away from warmer region to cooler region making them more spread out making them less dense and more spread out
convection current: in oceans and buildings (radiators)
to reduce convection stop the free flow of fluids
radiation: infra-red waves
hotter the object more radiation it emits
House is sealed so air cant leave —> which loses heat through convection
reduce heat loss by conduction: thick walls, materials will low thermal conductivity, cavity walls, air gap ( air is a poor conductor) filled with insulating foam
windows—> glazing single or (double) have different layers of glass with a small air gap reducing conduction
reduce friction in houses too: reduces the efficiency of energy transfer
power: rate of energy transferred p= e/t
power: rate of work done p= wd/t
efficiency: the ratio of useful energy output to the total energy input, expressed as a percentage
efficiency= useful energy (or power) output / total energy (or power) input
no object is 100% efficient energy is usually transferred as thermal energy