# Energy - Paper 1 Flashcards

## To revise the energy topic (paper 1)

What is a system?

an object or group of objects

Describe the energy changes when a ball is thrown upwards

Kinetic energy into GPE and thermal

Describe the energy changes when an object hits an obstacle

Kinetic into Thermal and sound

Describe the energy changes in a torch

Chemical into electrical into thermal and light

State the equation and all units for kinetic energy

kinetic energy (J) = 0.5 × mass (kg) × speed^{2} (m/s)

E = 0.5 x m x v^{2}

State the equation and all units for GPE

GPE (J) = mass (kg) × gravitational field strength(N/kg) × height (m)

GPE = mgh

Define specific heat capacity

the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.

State the units for specific heat capacity

J/kg °C

Define Power

Rate at which energy is transferred into a new form

State the equation with all units for Power.

Power (W) = energy (J)/ time (s)

P = E/t

Define 1 W

An energy transfer of 1 joule per second

State the conservation of energy

Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.

Define thermal conductivity

How well a material can insulate. The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material.

What does a larger thermal conductivity mean?

cvsvs

How can heat loss from a building be minimised?

Using thicker walls and materials with a lower thermal conductivity

Define efficiency

How effective a device is at converting its input energy into a useful output form of energy

State the equation for efficiency

efficiency = useful output energy / total input energy

State the 3 fossil fuels

Coal, oil and gas