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Differentiate between the six simple machines. (SPI 0707.11.1) Determine the amount of force needed to do work using different simple machines. (SPI 0707.11.2) Objectives

66. 2-Square Vocabulary Use pages 572-592 in your book to look up the definitions for each of the words above. The textbook definition is already written for you in the boxes on the right of each page. Use the information in the book to create your own definition and picture in the boxes on the left of each page.

Exit Ticket List 3 simple machines you learned about and give an example of how each one can be used.

Answer the Friday Question on your bellwork page Answer the Friday Question on your bellwork page. Get ready to turn it in! Bellwork 2-26-2016

Objectives Differentiate between the six simple machines. (SPI 0707.11.1) Determine the amount of force needed to do work using different simple machines. (SPI 0707.11.2)

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

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

Work YOURS: 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

Work or Not Work? OR OR YES NO YES NO

Force YOURS: 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

Work Input/Work Output YOURS: textbook: Work input is the work done on the machine. Work output is the work done by the machine. Examples: opening a paint can

Lever YOURS: 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)

Three Classes of Levers First-Class Lever Second-Class Lever Third-Class Lever Elementary School Middle School High School

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

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

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. The pulley changes the direction of the force. Elevators make use of fixed pulleys.

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

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

Wheel & Axle Effort force applied to a wheel is ____________ when it is transferred to the axle because the axle travels a ___________ distance than the wheel. multiplied, longer divided, longer multiplied, shorter divided, shorter

Inclined Plane YOURS: textbook: A simple machine that is a straight, slanted surface; a ramp. Examples: ramp or slide

Inclined Plane Tom wants to put a heavy box into the back of a moving truck. He is not strong enough to lift the box into the truck, so he uses a ramp to slide it up instead. The ramp is as an inclined plane that increases both the force needed to move the box and the distance over which the force is applied. increases the force needed to move the box while decreasing the distance over which the force is applied. decreases both the force needed to move the box and the distance over which the force is applied. decreases the force needed to move the box while increasing the distance over which the force is applied.

Wedge YOURS: textbook: A simple machine that is made up of two inclined planes and that moves; often used for cutting. Examples: knife, axe, door stop

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

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

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

Compound Machine YOURS: textbook: A machine made up of more than one simple machine. Examples: manual can opener

Mechanical Advantage YOURS: 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: It is 10 times easier to use a ramp to move a heavy object.