Rollers and Wheels
Which was made first, wheels or rollers?
Rollers were made first.
What is a pulley?
A pulley is a wheel with a groove in the rim. A rope sits in the rim of the wheel- which we pull to apply force.
What are the spikes on a gear called?
Teeth or cogs.
What is a lever?
Is a simple machine that uses leverage to life easier.
They usually consist of a long flat board and a fulcrum.
A simple machine is a device that makes our lives easier or helps lift and move heavy loads.
Wheels and rollers work by reducing which force?
Friction!
When you pull down on a fixed pulley, the load will move ____
up!
What is a gear?
A gear is a wheel with teeth that slot together, so that when one gear turns the other turns with it.
Explain what a class 1 lever is. What is an example of a class 1 lever?
Class 1 levers have the fulcrum in the middle and the load and effort are on either side.
ex. seesaw, light switch, scissors
Define- "Wheel and Axle"
It is a machine where a wheel is attached to an axle and when force is applied, they rotate together.
What is a disadvantage of rollers?
They have to be repositioned.
What are some objects or things that use a pulley?
Flag poles, blinds, crane....
How do you make gears turn in the same direction?
...by having two gears of the same size.
What is an example of a class two lever?
A class two lever is where the load is in the middle.
ex. wheelbarrow, bottle opener, suitcase...
Define "fulcrum"
The is the supporting part of a lever.
Draw a belt system that will go the same direction and the same speed
Answers will vary.
How does a pulley help us lift heavy objects?
When you pull down on a pulley, the downward force makes an upward force.
The gear that changes the direction of a gear train is called the ___________?
Idler gear.
Where do we move the fulcrum to make a load lighter?
You could move the fulcrum closer to the object you are lifting.
Define- "force"
It is a push or pull that causes a direction or movement.
An _________ goes in the wheel to help the wheel move?
axle
What happens when you use more than one pulley to lift a heavy object?
It magnifies the force we are using/applying.
Draw a gear system that will go opposite directions and different speeds
answers will vary
What happens when we move a fulcrum in a lever?
It creates a mechanical advantage by moving the fulcrum. It makes the force stronger.
Define- "friction"
Friction is the resistance that a surface or object and encounters when moving against something else.