Simple machines #1: Wheel and Axle
A wheel and axle is a machine that uses a wheel and an axle to move things.
For instance, a car uses a wheel and axle, the wheels on the car have a metal rod going through them both and without them they couldn't move as easy.
Simple Machine #2: The pulley
The pulley is a wheel with a grooved rim around it and through which a cord passes through it. It works like this, in the pulley their is a wheel and axle, just a small one thoughts. Then you put a cord or a rope through it and you pull to lift a heavy object. It decreases the effort needed to lift the heavy object. However, if it weighs heavier than you then you will need a double pulley, which uses two pulleys.
Simple Machine #3: The wedge:
The wedge is a machine that has a thick end and a thin end.
There are many uses for this machine, like a door. You can put this in the bottom of the door where it stays and the door will stay open. It works by the ends on it, the thick end provides support for the thin end as it stays under the bottom.
Simple machine #4: The inclined plane
Simple machine #5: The screw
The screw is rod with an inclined plane wrapped around it. It is useful for holding things in place.
Wheel and axle: MA=rw/ra mechanical advantage is 6
Inclined Plane:MA=i/h mechanical advantage is 2
Wedge:MA=i/w mechanical advantage is 2
Screw:MA= 3.14 x d/ l mechanical advantage is 15.71
Pulley: 2n mechanical advantage is 2
2nd class lever
2nd class levers are much different than 1st class levers, for instance the fulcrum isn't in the middle of it anymore, it is in the side. As you see in the picture above, the load is I'm the middle and the effort is on the side. A wheelbarrow is a good example of a 2nd class lever.
3rd class lever
3rd class levers are the most unique of all of them. It has the load on one end, and the fulcrum in the other. The effort is in the middle. A good example of a 3rd class lever is your arm.
1st class levers
A 1st class lever is the most simple. It has a fulcrum in the middle, and the effort and the load on the sides. A good example is a see-saw.