Pulley

Six Simple Machines

• Lever

• Wheel and Axle

• Inclined Plane

• Wedge

• Screw

• Pulley

​Today we will focus on levers, pulleys, and the wheel and axle.

All levers have three location of interest:

• Fulcrum or Fixed Point

• Point of Effort where work is done on the lever

• Load which is being moved

Classes of Lever

• Class 1 Lever

• Class 2 Lever

• Class 3 Lever

Class 1 Lever

has fulcrum located between effort and load. Class 1 lever includes crowbar, scissors, and pliers.

Class 2 Lever

has the load between the effort and load. The effort and resistance move in the same directions. Examples of class 2 levers are wheel barrows, bottle opener, and nutcracker.

Class 3 Lever

has the effort between the load and the fulcrum. Effort and resistance move in the same direction. Fishing rod, tweezer, and tongs are examples of class 3 levers.

Multiple Choice

WHAT ARE THE 3 MAIN PARTS OF A LEVER?

• FOOT, EFFORT, REPORT

• FULCRUM, STRUCTURE, EFFORT

• FULCRUM, EFFORT, LOAD

Multiple Choice

3. Which type of lever is this?

• First Class Lever

• Second Class Lever

• Third Class Lever

Multiple Choice

What is definition of the effort?

• The fixed point or pivot

• The point where the force is applied 

• The point where the weight/resistance is coming from

Pulley

A pulley is a grooved wheel that turns around and axle which is held in place by mounting bracket.

Three Kinds of Pulleys

• Fixed Pulley

• Movable Pulley

• Compound Pulley

Fixed Pulley

has the axle fixed on a surface and therefore does not move. Its fulcrum is at the center of the axle with load and effort on either side. It does not increase the magnitude, speed, or distance of the force. Fixed pulleys are used in flagpoles and clotheslines.

Movable Pulley

moves along the rope or wire. The fulcrum is at the edge of the wheel with the load at the middle of the axle and the effort at one end of the rope. It increases the magnitude of the force but decreases its distance. Examples of movable pulleys are ziplines, weight machines, and elevator cables.

Compound Pulley

is made up of a combination of two or more fixed and movable pulleys. Compound pulleys are used in ships and billboards.

Multiple Choice

What does this image represent?

• A pulley

• A wedge

• A lever

• A wheel and axle

Multiple Choice

What are two types of pulleys?

• wings, fries

• load. weight

• fixed, movable

• effort, force

Multiple Choice

Identify the type of pulley

• fixed

• moveable

Multiple Choice

Identify the type of pulley

• Fixed

• Moveable

• Block and Tackle or pulley system

Wheel and Axle

The wheel and axle is a machine that has a small disk or shaft called an axle that is attached to a wheel.

Multiple Choice

A shaft that is fixed to the center of a wheel allowing the wheel to rotate freely

• Axle

• Simple Machine

• Effort

• Simple Machine

Multiple Choice

A circular object that revolves with or around an axle

• Wheel

• Axle

• Force

• Work