Forces, energy and pressure Flashcards
Mass
Amount of stuff (atoms, molecules)in body.
Kilograms (Kg) or grams (g).
Using digital balance.
Mass never changes
Weight
Pull of gravity acting in the body.
It is a force.
Measured In Newtons (N).
Using newton meter.
Calculating weight
W=m x 10
Weight=mass x gravitational pull
Susan mass is 55kg.
What weight is she?
W=m x 10
W=55 x 10
W=550N
Force
Push or pull
Twist to turn
Effects of force
Change shape of object
Change speed
Change direction of motion
Force is measured using a…
Newton meter
The unit of force is…..
Newton (N)
What is friction
Force that opposes motion
What force causes a bobsleigh to get faster going down a hill?
Gravity
When does friction act
Two surfaces rub together
How is friction reduced on bobsleighs
Polish them
Air resistant position
Streamline
Does friction cat backwards.
Yes
What slows down aeroplanes
Air resistance drag
What is a transducer
Something that can change energy from one form to another.
Represented as an energy chain.
Falling stone
Kinetic➡️gravitational
Electric iron
Electrical➡️heat
Vacuum cleaner
Electrical➡️sound
Electrical light
Light➡️heat
Gravitational potential
Object gains weight when lifted higher.
Elastic potential
Energy stored in a wound up, stretched spring
Chemical
Energy stored in fuel, food and batteries
Electrical
Carried with electrical current
Kinetic
The energy an object has because it has been moving.
Light
Allows us to see things around us
Heat
Makes things warmer, melts solids and boils liquids
Sound
Energy produced when an object vibrates-makes noise
Nuclear
Energy with in an atom
Used in nuclear power stations
What si energy measured in
Joules (J)
Kilojoules (KJ)
How many joules in a kilojoules
1000 joules
Four ways human beings need energy
Walking
Talking
Lifting
Writing
A car is travelling 50 mph what does this mean?
This means that the car will travel 50 miles per hour.
How to calculate average speed
Distance(m)➗Time(s)
Do humans change forms of energy
Yes
What happens if humans eat more than they burn
They become fat
What happens if a human burns more energy than they eat
They will get tired easily
When is friction useful in the car
Between tyre and road.
Holding the steering wheel.
Gear stick-holding.
Breaks.
When is friction not helpful in a car
Air resistance.
Engine.
In science what tells us how concentrated a force is.
Force
Area
What is high pressure
Big force➕small area=high pressure.
Hammer=big force-pressing on a nail=small area.
Low pressure
Weight spread over a large area=low pressure
Camel is heavier than boy but doesn’t sink into the sand because it’s feet are large and cover more area which means it is low pressure.
