P8 Flashcards
What is a moment
The turning effect of a force
List two wats you can increase a moment
Increase the distance or the force
What are the units for moments
Mainly Nm (Newton meters)
How do you work out the moments
Force(N) x distance(m)
What is the centre of mass of an object
It is the point at which its mass can be thought of as being concentrated
How do you work out the moment of gears
Force x gear radius
Name some contact forces
Friction
Air resistance
Tension
Thrust
Name some non-contact forces
Gravitational
Magnetic
Nuclear
Electrostatic
What is a scaler
A scaler has physical quantities with size but NO direction
What is a vector
A vector has physical quantities with size AND direction
Examples of vectors
Acceleration
Force
Weight
Examples of scalers
Distance Speed Time Power Mass Energy
What is displacement
Displacement is distance without a change in direction
What is a force
A force is a push or a pull that acts on a object.
What is force measured in
Newtons (N)
What can a force do
Can change shape, change its motion and change its state of rest
What is a contact force?
They are forces that act between two object that are physically touching each other.
What happens when a contact force acts between two objects?
Both objects experience the same size force, but in opposite directions.
What are non-contact forces?
Forces that act between two objects that are not physically touching each other.
Weight and mass are
Directly proportional
What is an objects centre of mass?
The point representing the mean position of the matter in a body (the single point at which weight is acting)
