Chapter 37 - Moments and Centre Of Gravity Flashcards
In physics, what do we call the fixed point or line through which something swings?
The fulcrum
In what two ways can the turning effect of a force be increased?
- by increasing the force itself
- by increasing the distance from the applied force to the fulcrum
What is the measure of the turning effect of a force called?
The moment (or torque) of the force,
What is the moment of a force?
A measure of its turning effect
How do you calculate the moment of a force?
Force x perpendicular distance from the force to the fulcrum = moment of a force
Give 3 everyday examples of levers
- a door handle
- a spanner
- a lightswitch
What is a lever (definitttiooonnnn)
A lever is any rigid body that is free to turn about a fixed point or axis called a fulcrum
What is the law of the lever?
When a lever is balanced by any number of forces, the sum of the clockwise moments acting on it is equal to the sum of the anti-clockwise moments
What is the centre of gravity?
The centre of gravity of an object is the point through which the weight of the object appears to act
Where are the centres of gravity of regularly shaped symmetrical objects?
At their centres
When can an object be balanced in relation to its centre of gravity?
If it’s supported either at its centre of gravity or at a point vertically above or below its centre of gravity
What is the stability of an object linked to?
The stability of an object is linked to the position of its centre of gravity
What is an object that is balanced said to be in?
Equilibrium - see page 280 of text book for more on this
When are objects in stable equilibrium?
A body is in stable equilibrium if, when slightly moved or tilted, it’s centre of gravity rises
When are objects in unstable equilibrium?
A body is in unstable equilibrium if, when slightly moved or tilted, its centre of gravity falls
