First, rank the following words from 0-5 (0= you have never heard of this word & 5= you know the word VERY well). Second, explain what the following terms mean in your own words: –Machine –Simple machines –Work –Force –Work input/Work output –Lever -Pulley -Wheel & axle -Inclined plane -Wedge -Screws -Compound machine BELLWORK 4/6/15

Simple Machines April 6, 2015

Differentiate between the six simple machines. (SPI ) Determine the amount of force needed to do work using different simple machines. (SPI )

TEXTBOOK: A machine is a device that makes work easier by changing the size or direction of a force. Examples: wheelchair, scissors, chopsticks

TEXTBOOK: A machine or simple device without moving parts. Examples: lever, pulley, wheel & axle, inclined plane, wedge, screw

TEXTBOOK: Work is the transfer of energy to an object by using a force that causes the object to move in the direction of the force. Work is done on an object if two things happen: 1) the object moves as a force is applied, 2) the direction of the object’s motion is the same as the direction of the force. Examples: pushing a ball up a hill

OR YES NOYESNO

To be considered work the direction of what two things must the same? Force and Motion

Work or Not Work? Problem #1: –D.J. carries a backpack from the cafeteria to the 8 th grade hallway. Problem #2: –Austin applies force to (pushes) a brick wall.

Work or Not Work? Problem #3: –Mya pushes a stack of books across the floor. Problem #4: –Alexis wears a backpack and climbs up the side of a mountain.

TEXTBOOK: A push or a pull exerted on an object in order to change the motion of the object; force has size and direction. Examples: people, bulldozer, static electricity

The equation for WORK is… work= force x distance or W = F x D

Work Problem #1: --Kammi uses a lever to lift a large stone from the ground. Kammi applies a force of 50 newtons and moves the stone 5 meters. How much work is being done by Kammi?

Work Problem #2: --Mariah wants to move a stack of magazines from one room of her house to another. Using a wheel and axle, Mariah applies a force of 100 newtons and moves the stack 10 meters. How much work is being done by Mariah?

The equation for FORCE is… Force = work _________ distance or F = W / D

Force problem #1: --Tabetha performed 100 joules of work by moving a pile of rocks 10 meters with a lever. What was the force on the rocks?

Force Problem #2: -Cameron performed 500 joules of work by lifting a car 50 meters with a pulley. What was the force on the car?

TEXTBOOK: Work input is the work done on the machine. Work out put is the work done by the machine. Examples: opening a paint can

The Six Simple Machines

Lever

TEXTBOOK: A lever is a simple machine that has a bar that pivots at a fixed point, called a fulcrum. Examples: first-class lever (see saw), second-class lever (wheelbarrow or soda bottle opener), third-class lever (lifting weights or hammering a nail)

Write the question & answer.

First-Class LeverSecond-Class LeverThird-Class Lever Elementary SchoolMiddle SchoolHigh School

First-Class LeverSecond-Class LeverThird-Class Lever 2nd class- the load is between the fulcrum and the force 3rd class- the force is between the load and the fulcrum Elementary SchoolMiddle SchoolHigh School 1st class- fulcrum is placed between the load and the force

Which of the following correctly explains why one of the above levers can lift the object with less effort force? A.Lever X will require less effort force because its fulcrum is closer to the object than lever Y's fulcrum. B.Lever Y is a third-class lever and will require less effort force than lever X, which is a second-class lever. C.Lever X is a third-class lever and will require less effort force than lever Y, which is a second-class lever. D.Lever Y will require less effort force because its fulcrum is closer to the input force than lever X's fulcrum.

The Six Simple Machines LeverPulley

TEXTBOOK: A simple machine that has a grooved wheel that holds a rope or a cable. Examples: fixed, moveable, block and tackle

The pulley changes the direction of the force. Elevators make use of fixed pulleys. Movable pulleys do increase force, but they also increase the distance over which the input force must be exerted. A fixed pulley and a movable pulley are used together; the mechanical advantage of a block and tackle depends on the number of rope segments.

Which of the pulley systems shown below will lift the weight using the least amount of effort force?

The Six Simple Machines LeverPulleyWheel & Axel

TEXTBOOK: A simple machine consisting of two circular objects of different sizes. Examples: car’s wheel & axle, faucet

Effort force applied to a wheel is ____________ when it is transferred to the axle because the axle travels a ___________ distance than the wheel. A.multiplied, longer B.divided, longer C.multiplied, shorter D.divided, shorter

The Six Simple Machines LeverPulleyWheel & Axel Inclined Plane

TEXTBOOK: A simple machine that is a straight, slanted surface; a ramp. Examples: ramp or slide

The Six Simple Machines LeverPulleyWheel & Axel Inclined PlaneWedge

TEXTBOOK: A simple machine that is made up of two inclined planes that move; often used for cutting. Examples: knife, axe, door stop

Select the choice that best completes the following sentence. When an axe is used to chop wood, A.the axe blade acts as a wedge and changes the direction of the input force. B.the axe blade acts as a wedge and does not change the direction of the input force. C.the axe blade acts as a lever and does not change the direction of the input force. D.the axe blade acts as a lever and changes the direction of the input force.

The Six Simple Machines LeverPulleyWheel & Axel Inclined PlaneWedgeScrew

TEXTBOOK: A simple machine that consists of an inclined plane wrapped around a cylinder. Examples: screw, light bulb

Which of the screws below requires the least amount of effort force to turn? W. X.Z.Y.

TEXTBOOK: A machine made up of more than one simple machine. Examples: manual can opener

TEXTBOOK: A machine’s mechanical advantage is the number of times the machine multiplies force; how much easier it is to do the work using that specific machine. Examples: Mechanical Advantage It is 10 times easier to use a ramp to move a heavy object.

Agendas and HW (p in workbook) out on desk!! Answer your Bellwork in your composition book. What type of machine can be found on at least half the students in this room right now? What kinds of machines were common 50 years ago? 100 years ago? Are any of the same machines around today that were common in the 1800s? What has changed about those same machines today? BELLWORK 3/14/12

Agendas out on desk!! Answer your Bellwork in your composition book. Think about the differences between the six simple machines. Which simple machines could you use to raise heavy objects? Which simple machines could you find in a kitchen? Describe how you would use these machines. BELLWORK 3/15/12