P2 - Energy Flashcards
What is friction?
Force that opposes a surface which is moving over another
What is the formula for work?
Force * distance
Why do falling objects heat up?
The friction between the object and the air (air resistance) generates heat
What does friction cause?
The work put into moving the object is dissipated as heat
What is the law of conservation of energy?
Energy can’t be created or destroyed but only transferred into different types of energy
What are the 2 types of friction?
Air resistance
Contact friction
In what way is energy transferred in friction?
Kinetic energy is transferred to heat
What is work measured in?
Joules
What is the gravitational field strength of Earth?
10 N/kg
What is the formula for calculating gravitational potential energy?
Mass * gravitational field strength * height
What happens to gravitational potential energy when an object falls to the ground?
It is converted to kinetic energy
How is gravitational potential energy put to use in the real world?
In hydro-electric power stations
If a mass of 5kg is lifted 10 metres above the ground, what is the gravitational potential energy of the object?
5 * 10 * 10
500 Joules
What is power?
The rate at which work is done
What is power measured in?
Watts
