What is a vector quantity?
One that has magnitude (size) and a specific direction.
Newtons 1st law part one.: when resultant force on a body is zero it is either ….
… moving at constant speed or is at rest
Newtons first law part two: when resultant force on a body is not zero it is ….
… changing speed or direction.
Define mass
The amount of matter something is made of
What is mass measured in?
kg
Define upthrust
The force causing things to float
Define thrust
The force from an engine
What is the electrostatic force?
The force between chargeed objects.
Like charges repel, opposite charge attract.
Define weight
The force on an object due to gravity
What is weight measured in?
Newtons
What is force measured in?
Newtons
What is friction?
A force that resists motion, caused by two surfaces rubbing together.
What direction will friction act?
Opposite to the direction the object is moving
When forces are balanced the object is travelling at _ _ _ _ _ _ _ _ _
constant speed
When forces are unbalanced the object is
_ _ _ _ _ _ _ _ _ _ ,
changing _ _ _ _ _ or
changing _ _ _ _ _ _ _ _ _.
accelerating,
changing shape, or
changing direction
What is the name for ‘the maximum speed of an object where air resistance is equal to weight or thrust and so it cannot accelerate’
terminal velocity
What is terminal velocity?
The maximum speed of an object as it falls through a fluid (like air)
When does terminal velocity occur?
When the drag force is the same size as the weight of the object.
What is the relationship between drag and speed?
The faster the object the larger the drag force
What size is g (graviational field strength) on earth?
10 N/kg
If an object is falling on earth, what is it’s acceleration?
10 m/s2
What is resultant force?
The overall force acting on an object
