Simple Machines

Six Simple Machines

Just about every machine we have today is comprised of these ______.

exisited for thousands of years

incline plane

pulley

wheel and axele

wedge

lever

screw

Pros of Simple Machines

Reduce friction, effort, and spreading it over greater distance or time, so there’s less efforts required at a given moment.

Incline Plane/ Ramp

Mechanical Advantage of things such as

Ramps

Incline Plane Example

Let’s say you have a truck, and you wanna load something into the back of the car.

You could lift it straight up, or you could take it up an ______ or RAMP into the back of the truck.

Lifting straight up covers less distance. The ramp may be 3- 4x as far, but that means if its 4x as far up the ramp, you’re doing ¼ amount of effort.

Wheel and Axle

An axle is the point around which the wheel rotates

Wheel and Axle Example

Instead of the truck, having to be drug across the ground because it rides on wheels, the wheels reduce the friction of the truck with the ground so a wheel and axle is very useful for reducing friction

The Lever and Fulcrum

A _______ is a simple machine that helps you lift or move things more easily. It has three main parts:

1. Fulcrum – The pivot point where the lever balances or turns.

2. Effort – The force you apply to make the lever move.

3. Load – The object you are trying to lift or move.

   • If you push down on one side of the _____, the other side goes up (like a seesaw).

   The closer the fulcrum is to the load, the easier it is to lift.

Lever and Fulcrum Example

Fulcrum in the middle

When having these two objects balanced, larger objects are going down.

To balance out, remember, closer something is to the fulcrum, the more force is exerted upon it and further away from the fulcrum, the more force that things exerts.

• Either move the smaller (less massive) object further from the fulcrum or we move the large object toward the fulcrum

The Pulley

It has a wheel and axle, but with a rope or cord wrapped around it and it can be used to lift objects.

This allows us to pull with gravity (mechanical advantage)

-It also uses friction reducing the wheel and axle, and allows us to redirect force in whatever direction we want.

The Pulley Part 2

Can also have multiple pulleys around which the rope wraps.

e.g. we’re lifting a object and we wrap the rope around it several times around each pulley then pull.

The pulley w/ two wheels has much more advantage because you have to pull more rope to get this object to travel the same distance with less force.

The Wedge

Variation of the incline plane

Let’s say you’re trying to split two blocks of wood apart, we take the wedge and drive it into the middle

We pound on it, driving the wedge in until one of the sides goes up and it splits apart

Similar to an incline plane, except you take the wedge into the object

The Screw

similar to an incline plane that’s wrapped around a wheel and axle

As you spin the screw, the screw pulls down in the wood, the wood rides up the incline plane, but instead going up the incline plane diagonally the same distance is being wrapped around the axle