Inclined Plane Notes

An inclined plane is a simple machine that consists of a flat, slanted surface. It can also be called a ramp.

Big Ideas

The longer and lower the inclined plane is, the less effort it takes to move the load.

Mechanical Advantage (ma) is the number of times a machine multiplies your effort. There are different formulas to calculate ma for each machine.

The ma for an inclined plane= Length of IP / Height of IP

There is a trade off between force and distance. If you use a longer board, the load is easier to lift, but, you must move it over a longer distance.

Wedge and Screw Notes

Big Ideas

Wedge- is an inclined plane that moves. Sometimes a wedge is a double-sided inclined plane.

• Wedges help us to lift, cut, split, and stop things.
• The longer and thinner the wedge is, the easier it is to lift or split things. This increases mechanical advantage.
• The formula for mechanical advantage for a wedge is MA = length of wedge/ thickness of wedge
• Examples: pens, pencils, nails, knives, axes, chisels, fronts of boats, rooftops.

Screw- is an inclined plane that is wrapped around a central bar or cylinder. There are 2 kinds of screws-fasting and lifting.

• Screws can fasten things together or lift things up.
• The longer the screw and the closer together the threads are the greater the mechanical advantage
• Trades force for distance: It is easier to turn but we must turn it more times.

Lever Notes

Lever – Is a simple machine that consists of a bar that is free to rotate around a pivot point called a fulcrum. It helps us in many ways.

Big Ideas:

                                                        Distance from the load to the fulcrum
This means that we want our effort far away from the fulcrum and the load closer to the fulcrum.

                                                                          
We can push down↓ to lift up ↑.

1st Class                       E___________L or L___________E
                                                F                               F
2nd Class                      E___________F or F___________E
                                                L                               L
3rd Class                       F___________L or L___________F
                                                E                               E
* A 3rd class cannot multiply effort force because the effort can never be farther away from the fulcrum than the load. It cannot have M.A.; it only increases distance which can
be helpful.  

Force: any push or pull capable of moving or stopping objects

Wheel and Axle Notes

A wheel and axle is a simple machine made up of two circular objects of different sizes. The wheel is the larger object which turns about the axle. The wheel is locked to a central axle so that when one is turned the other must turn.

BIG IDEAS:

1. Because the wheel is larger than the axle, it always moves through a greater distance than the axle. The wheel and axle works as a 3rd class lever when the effort is applied to the axle.
2. Force applied to the wheel is multiplied when it is transferred to the axle, which moves a shorter distance. The wheel and axle works as a 2nd when the effort is applied to the wheel
3. Mechanical advantage depends on the difference in size between the radius of the wheel in comparison to the radius of the axle.  You want a wide wheel and a thin axle for more m.a.  Example: If the wheel is 10 inches around and an axle is 1 inch around, you need only one tenth of the force when you turn the wheel to lift the load. In this case, our effort force is multiplied 10 times.

Mechanical advantage is the number of times that a machine multiplies the effort force. It can be expressed mathematically:            
                                                MA   =     radius of the wheel               
                                                                 radius of the axle

Some real life examples of wheel and axles are: water wheels, door knobs, gears, screw drivers, and steering wheels.