Work Power Machines Simple Machines

http://player. discoveryeducation. com/index. cfm http://player.discoveryeducation.com/index.cfm?guidAssetId=7AB8EB45-B3EC-4B63-AF0B-1723AFDB001C&blnFromSearch=1&productcode=US

Simple Machines Ancient people invented simple machines that would help them overcome resistive forces and allow them to do the desired work against those forces.

WORK Work is done on an object when the object moves in the same direction in which the force is exerted. Work= Force x Distance

Power The rate at which work is done Power= Work Time

A mechanical device that changes the direction or amount of force Simple Machine pg.2 A mechanical device that changes the direction or amount of force The simplest mechanisms that provides mechanical advantage

Machine pg 3 A device that allows you to do work in a way that is easier and more effective

The forces you exert on a machine Input Forces PG 4 The forces you exert on a machine

The force the machine exerts on an object . Output Forces pg 4 The force the machine exerts on an object .

Input force x Input distance Work pg 4 Input Work Input force x Input distance Output Work Output force x Output Distance

Mechanical Advantage pg 5 The number of times a machine increases a force exerted on it. Mechanical Advantage Formula Output Force Input Force

Simple Machines Incline Plane Wedge Screw Lever Fulcrum Wheel and axle Pulley

Inclined Plane pg. 6 A flat sloped surface. Ex. Ramp Input force less than output force Mechanical Advantage Ideal mechanical advantage= Length of incline Height of incline

Wedge pg. 8 A device that is thick at one end and tapers to a thin edge at the other end. Ex. Ax blade Zippers Pencil Sharpener Mechanical Advantage = Length of wedge Width of wedge

When you bite into an apple your incisors act like wedges Working Wedges When you bite into an apple your incisors act like wedges

A rigid bar that is free to pivot, or rotate, on a fixed point. Levers pg 10 A rigid bar that is free to pivot, or rotate, on a fixed point. Fulcrum- The fixed point that a lever pivots around.

The body consist of levers of bones and muscles. Living Levers The body consist of levers of bones and muscles. The joint acts as a fulcrum

Three Classes of Levers pg 10 1st Always change the direction of the input forces. Ex. Paint Can Opener, scissors, and seesaws.

Three Classes of Levers pg 10 2nd Increase force but do not change the direction of the input force Ex. Wheelbarrel Doors Bottle Openers

Three Classes of Levers pg 10 3rd Increase distance but do not change the direction of the input forces Ex. Fishing Poles Baseball Bats

Mechanical Advantage pg 11 Ideal Mechanical Advantage= Distance from fulcrum to input force Distance from fulcrum to output force

Screws pg 12 An inclined plane wrapped around a cylinder. This spiral inclined plane forms the threads of the screws. Ex. Bolts Light Bulbs Jar lids Mechanical Advantage = Length around the threads Length of the screw

Wheel and Axle pg. 14 Made of two circular or cylinder objects fastened together that rotates about a common axle. Largest radius called wheel Smallest radius called axle Ex. Screwdriver Handle wheel shaft is axle Doorknob Car Steering wheel

Ideal Mechanical Advantage pg 14 Radius of wheel Radius of axle Ex. Screwdriver wheel is 1.5 cm and the axle is .3 cm. What is the advantage

Made of a grooved wheel with a rope or cable Pulleys pg 16 Made of a grooved wheel with a rope or cable

Types of Pulleys pg 16 Fixed Pulley Does not change the amount of force applied. It does change the direction of the force Movable Pulley Decreases the amount of input forces needed. It does not change the direction of the force. Block and Tackle Combination of Fixed and Movable pulleys

Ideal mechanical Advantage pg 16 The number of sections of rope that support the object

A machine that utilize two or more simple machines Compound Machines pg. 18 A machine that utilize two or more simple machines

Ideal Mechanical Advantage pg. 19 Product of the individual ideal mechanical advantage of the simple machines that make it up.