Simple Machines Notes

Simple Machines Notes

What is Work? The application of a force to an object to move it a certain distance in the direction of the force.
Equation: work = force x distance
What is Force (F)? a push or a pull
What is Distance (d)? an amount that an object moves
When is work actually done? Only when the object moves in the same direction of the force that is being applied. NO movement NO work.

Simple Machines

•______6______basic types

•Designed to ___make work easier______

•Have ______no______moving parts

•Can combine to form ____complex machines____ (like cars)

Inclined Plane

•What is it? A straight, slanted surface. / Picture:

•Example: Ramp
•How does it make work easier? It is easier to push an object up a ramp than it is to lift the same object straight up to the same height.

Wedge

•What is it? Inclined plane that is wider or thicker at one end than the other. / Picture:

•Example: Knife blade or axe
•How does it make work easier? When, moved it is used to cut, split, or pry apart objects.

Screw

•What is it? Inclined plane that is wrapped around a cylinder / Picture:

•Example: screw, bottle cap
•How does it make work easier? When turned a small force is applied over the long distance of the screws threads

–The amount of work for a screw depends on the ___number of thread___, which is actually the length of the inclined plane.

Lever

•What is it? Made up of a bar that pivots at a fixed point called a fulcrum.

–The force applied to the lever is called the ____effort______.

–The object moved is called the _____load_______.

•Are classified into ______3______different groups.

–These groups are based upon the locations of the __fulcrum______, ____load______, and the ______input force______.

First-Class Lever

•Arrangement: fulcrum in the middle, load and force on the ends. / Picture:

•Example: seesaws

Second-Class Lever

•Arrangement: load (resistance) is in the middle, force and fulcrum are on the ends. / Picture:
The wheelbarrow is the second class lever.
•Example: wheelbarrow, nutcracker

Third-Class Lever

•Arrangement: force(effort) is in the middle, the load and fulcrum are on the ends / Picture:

•Example: baseball bat, fishing rod

Pulley

•What is it? A rope or chain wrapped around a wheel. Load is attached at one end of the rope and a force is applied to the other end.

•A single pulley makes work easier by _changing the direction of the effort force__.

______.

–When you pull __down___ on the rope, the load moves _____up______.

•A double pulley makes work easier, not only by changing the direction of the force, but also by ______multiplying the effort.______.

•Each pulley multiplies the effort. 4 pulley means 4 times the effort.

•

Wheel and Axel

•What is it? Consists of 2 circular objects of different sizes. Wheel is always larger than the axle. / Picture:

•Example: Door knob
•How does it make work easier? By getting more force from the effort put in when compared to the amount of distance.