Forces and energy Flashcards
What type of forces are there?
Contact forces
Non-contact forces
What type of contact forces are there?
Fricition
Elastic force
What type of non contact forces are there?
Gravitational force
Magnetic force
What is friction?
It is the force that opposes motion between two surfaces in contact
What is elastic force?
It is the force acting on a stretched or compressed elsatic object to return it to its original shape
What is gravitational force?
It is the force that attracts two objects towards each other
What can Earth’s gravitational force do?
-Pull all objects towards earth
-Keep the moon obiting around earth
What is the difference between mass and weight?
-Mass is the amount of matter in an object while weight is the gravitational force exerted on an object
-Mass does not change with location while weight does
-The SI unit for mass is kg while for weight is Newtons
-Mass can be measured by electronic balance and beam balance while weight can be measured by spring balanced
What is magnetic force?
It is the force extered between a magnet and another magnetic material/magnet
When two objects interact, they exert a force on one another which causes…
Transfer of energy between objects
Transfer of energy between forces can cause…
-Move a stationary
-Change the speed of an object
-Change the direction which an object moves
-Stop a moving object
What is pressure?
An effect of force acting on an object
How is pressure calculated?
Force divided by area
How does liquid pressure work?
The pressure due to the liquid increases as it goes deeper
What is work done?
Through the application of a force of an object to move in the direction of the force
For work to be done on an object, what must it satify?
-A force is applied on an object
-The object moves
-The object moves in the same direction as it is applied on
What is the forumla for work done?
Force in Newtons times Distance travelled in metres
Work done is zero when…
-The force applied is zero
-The distance moved is zero
-The distance is perpendicular to the direction applied
What is the principal of conservation?
-Energy csannot be created of destroyed
-Energy can be transferred from one store to another
-Total energy in an isolated system is constant
What are the six types of energy stores?
-Elastic potential store
-Chemical potential store
-Gravitational potential store
-Kinetic store
-Internal (thermal) store
-Nuclear store
What is the formula for the size of an energy store?
Mass of the body in kg times speed of the body in m/s
What is the formula for gravitational potential store?
Mass of the body in kg times the height in m times the gravitational field strength (10N/kg)
Where does energy come from?
-fossil fuels
-sun
-solar power
-hydroelectric energy
-wind energy
-Geothermal energy
-Biofuels
-Nuclear store
