Simple Machines
T/F: Pulleys and gears are both examples of simple machines.
TRUE!
T/F: Pulleys always make the load lighter.
False!
Gears have ______ that fit together.
Teeth
An elevator uses what kind of simple machine?
A pulley
What does "mesh" mean?
When gears fit together.
T/F: All simple machines use wheels.
False!
Name the three type of pulleys.
Fixed, moveable, compound/ combined.
The first gear in a gear train is called the ___________.
Driver
Name a pro and a con of a bicycle compared to a car.
Pros: less expensive, better for the environment, ...
Cons: no protection from the weather, usually only one person can fit...
What are the 3 names of the gears in a gear train? Explain what they do.
Driver, idler, driven
T/F: Simple machines usually have many complicated moving parts.
FALSE! Simple machines usually have few (or no) moving parts.
Name three parts of a pulley system.
Load, axel, wheel, rope, effort force, groove,...
In a gear train, gears move in _________ (opposite/ the same) directions.
opposite
Name 3 examples of things that use gears.
Can opener, car, clocks, conveyer belts, escaltors...
What does "direction" mean when we are talking about gears?
Which way the gear turns, clockwise or counter clockwise
What are simple machines?
Simple machines are basic devices that make work easier. They can change the direction of force or the amount of force needed.
T/F: A combined/ compound pulley always has only 2 pulleys.
False! A combined pulley has to have at least 2 pulleys, but it can be more.
Explain a gear chain and give 1 example.
A gear chain is 2 gears (technically called sprockets) that move thanks to a chain. Gears move in the same direction. A bike is an example.
Name 2 pros and 2 cons of an escalator.
Pros: you can move faster, it can help you to move heavy things, they can be used as stairs if it breaks down...
Cons: not everyone can use them, they use energy, they create waste when they need to be replaced...
Define gearing up and gearing down.
Gearing down - small to large for greater force
Name one other example of a simple machine.
Lever, wheel + axel, inclined plane, wedge, screw
What are the 2 main advantages of a combined pulley?
It reduces the amount of force needed to move the object by 50% and it can be pulled down.
How do the number of teeth on a gear affect how it moves and the force?
More teeth means it moves slower and has greater torque (force), less teeth means it moves faster with less torque (force).
What is the difference between a gear train and a gear chain?
Gear train is 3+ gears together.
Gear chain is 2+ gears that do not mesh, but move in the same direction thanks to a chain.
Define torque.
Torque is the twisting force.