Pulley Systems Flashcards
How do pulleys work ???
They use a mechanical advantage to lift/ pick up objects
Often being wheel shaped with a groove to allow a cord to sit inside
Why might a pulley be notarized ?
Increase the amount of weight that can be lifted
What are the benefits of a pulley ?
Simple and manouverable way to love larger objects
Easy to transports where they are needed
Con- require somewhere stable to hang
How does a single pulley work ?
Changes the direction of force to make a pulling down easier than lifting up
Example include cranes, raising a flag and adjusting window blinds
What is the description ( mechanical avndtage) of a single pulley?
It has a mechanical advantage of one
Mechanical advantage is equal to sections of rope used
If additional pulleys are added to a single pulley what is created ?
An actual mechanical advantage because it means you need half the force to lift and object
It’s known as a block and tackle
What are block and tackles used for and what would adding more wheels do ?
Used to lift large, difficult shaped objects such as furniture
It would increase the load it can lift
If a one rope pulley is lifting a 10N load what’s the load required to lift ?
10N
And extra pulley system wouldn’t take additional strain only a section of rope can take weight
If there is a load of 10N and 2 sections of rope what would the force be ?
5N as it’s halved the force
Meaning it has a mechanical advantage of 2
If an object of 300N is being lifted and 3 pulleys are used what is the force required ?
300N divided by 3
100N
How do belts work ?
Belt drives transfer movements from on data ting pulley to another with each one being held by a shaft
Usually being made of any material however a pulley belt is made from rubber
Why are there grooves on a pulley belt ?
To help them grip and turn
What are some examples of belt driven mechanisms ?
Winches
Treadmills
Washing machines
How do you work out the velocity ration ?
How do you work out output speed ?
- Velocity ratio= diameter of the driven pulley/ diameter of the driver pulley
- Output speed= input speed/ velocity ratio
How do you work out which pulley is which in a belt system ?
The bigger one is always the driven pulley with the smaller one being the driver pulley
