5.4 Forces (moments, levers and gears) Flashcards
What is a moment?
The turning effect of a force about a pivot
What can the direction of the moment be?
clockwise or anticlockwise
What is the equation for moment?
moment = force x perpendicular distance from pivot
m = f x s
What is s?
distance
The further the force is applied from the pivot, what increases?
the moment exerted by it
What are the principles of moments?
- When two or more forces can combine to produce no overall turning effect, this is called the principle of moments
- When an object’s anticlockwise moment is equal to the clockwise moment, the object is in equilibrium and won’t turn
If an object is in equilibrium, what can be said about the moments acting on the object?
The clockwise moments are equal to the anticlockwise moments
What distance measurement is used when calculating a moment?
The perpendicular distance from the pivot to the line of action of the force
If the anticlockwise moment is bigger, where will the seesaw turn?
anti-clockwise
What do levers do?
It increases the distance from the pivot to where the force is applied
What are levers?
force multipliers and increase the size of the force acting on the object, hence less force is required for the same moment
What do gears do?
they transmit rotational effects
What happens when a small gear turns a big gear?
It gives a low speed but a high turning effect
What happens when a large gear turns a small gear?
It gives a high speed but a low turning effect
If one gear turns, what will the other gear do?
turn the opposite direction
what are gears referred to as?
they are referred to as circular discs with teen which interlock one another
What three parts make up a lever system?
- Load
- Effort
- Pivot
How can a lever be used as a force multiplier?
If the distance between the effort and pivot is greater than the distance between the pivot and load, the force applied on the load is greater than the effort force. this is since the moment on both the effort and load must be the same
Give an example of when a lever may be used to multiply a force
A wrench, which has a long handle so that the force applied by the user is multiplied
What determines the moment of a gear wheel?
the size of the wheel
Describe the moment and speed of a larger gear being driven by a smaller gear
The larger wheel will rotate more slowly but will also produce a larger moment
