Work & Machines

Simple Machines

Chapter 4

Section 3

Simple Machines

• Inclined Plane Family • Lever Family

Lever Family

• Simple Lever• Pulley• Wheel & Axle

Levers

• All have a rigid arm that moves on a fulcrum– Wheel barrel– Teeter-totter

K’NEX Hammer

• Increased di causes increased Fo

K’NEX Nut Cracker

• Increased di causes increased Fo

K’NEX Scale Balance

Pulley

• A modified lever that uses a wheel instead of a fulcrum

• Block & Tackle– Multiple pulleys put

together as a single unit

• Ex. Garage doors

Wheel & Axel

• A pulley (wheel) connected to a shaft (axle)

• Steering wheel– Bigger = easier

• Screwdriver handle– Thicker = easier

Inclined Plane Family

• Simple Inclined Plane• Wedge• Screw

Simple Inclined Plane

• Changes magnitude & direction of the force

• Ramp– Decreases Finput

– Increases dinput

Wedge

• Two modified incline planes, back-to-back– 1 downward force

• Turns into 2 outward forces

– Blade – Splitting wedge– Nail

Screw

• An inclined plane wrapped around a cylinder– Screws– Jar lids– Spiral staircase

Compound Machine

• A machine that combines 2 or more simple machines

• Scissors– Handles

• 2 levers – joined at a common

fulcrum

– Blades• 2 wedges,