Physics Flashcards
Resultant force
a resultant force is many different forces that act on an object.
More than 1 force acting on an object can be replaced by a single overall force. This is called the resultant force
how is a force measured
In newtons
a balanced forced
an object that is not moving
an object that is moving continues to move at the same speed and in the same direction
an unbalanced force
an object thats not moving but starts moving
an object that is already moving but changes speed or direction
gravity
gravity is a force between all object , the size of the force depends on the mass of the objects
the bigger the size, the bigger the force
the size of the force depends on the distance between the objects
the force of gravity on something is called its weight
mass and weight
Mass is a measure of the amount of material an object is made of it is measured in kgs
Weight is the force of gravity on an object. it is measured in newtons
why are astronauts described as weightless in space
no gravity in space acting on them
calculating weight
W= mass x gravity
kg what is the weight of a man who has a weight of
gravity on earth is 10 N/kg
W=70 x10= 700N
What is a force
Forces cannot be seen, but their effects can
Measured in newtons
They usually act in pairs . They always act in a certain direction
A newton meter
measures a force
What can a force do
- speed up - like kicking a ball
- slow down -like drag or air resistance
- change direction - hitting a ball with a bat
- turn (torque) - like turning a spanner
- change shape - like stretching, twisting
