Load Effort. Work = (Force)Distance = (F)d. Mechanical Advantage = R E MA = 12/20/11

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Cody Jefferson
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Transfer kine+c energy (the energy of mo+on) educe the effort needed to move a load Change the direc+on or amount of mo+on Change the type of mo+on (rotary to straight line) () the input force ither

1 Transfer kine+c energy (the energy of mo+on) educe the effort needed to move a load Change the direc+on or amount of mo+on Change the type of mo+on (rotary to straight line) () the input force ither the user or some type of engine supplies this force. () the output force. Also known as the force resis+ng the mo+on. Mechanical Advantage (MA) a measure of how much effort is decreased by the simple machine. Mechanical Advantage Work : The force applied on an object +mes the distance traveled by the object. Work (Force)Distance (F)d Force Star+ng Posi+on Distance Finishing Posi+on 1

Power is the rate at which work is performed. Fric:on results from two bodies moving against each other in different direc+ons. Fric+on always opposes mo+on and makes doing work harder.

2 Power is the rate at which work is performed. Fric:on results from two bodies moving against each other in different direc+ons. Fric+on always opposes mo+on and makes doing work harder. ubricants (graphite, oil, grease, silicone) and bearings are used to combat fric+on. Some+mes, fric+on is a good thing! fficiency is the ra+o of the work that results to the amount of work put into the machine. nergy describes the amount of work that can be performed by a force. P W t P power W work t +me energy W A lever is a s+ff bar which rotates around a point called the fulcrum. The forces on the lever are the () and the load (). ength (distance) from fulcrum to ength (distance) from fulcrum to () 2

Moment 1 Moment 2 Force 1 x distance 1 Force 2 x distance 2 300 lb x 4 X 1200 lb x 1 X 1200 X- lb 1200 X- lb You are given a board that is 8 feet long and

3 Moment Force x distance to fulcrum CW (- ) CCW (+) The is posi+ve because it is rota+ng in a counter clock wise rota+on around the fulcrum. The is nega+ve because it is rota+ng in a clock wise rota+on around the fulcrum. Moment 1 Moment 2 Force 1 x distance 1 Force 2 x distance lb x 4 X 1200 lb x 1 X 1200 X- lb 1200 X- lb You are given a board that is 8 feet long and a rock to use as a fulcrum and you need to lix a heavy object. Where would you place the rock? Why? Mechanical Advantage 4 X 1 X lb 300 lb 4 Place the rock as close as possible to the load becomes very large. becomes very small. or () () 3

4 If greater than, then MA greater than 1 Since greater than, then MA greater than 1 If less than, then MA less than 1 Given: 6 X, 3 X, 1 lb Find. Since the less than, then MA less than 1 Solu:on: 6 X 3 X 2 So.. 2 1lb 2 lb 4

5 Given: 8 lb, 4 X, 4 lb Find. Solu:on: 4 X 8 lb 4 lb 2 X 5

6 A wheel with a 12 inch radius is used to turn an axle with a radius.5 inches. What is the mechanical advantage? Mechanical Advantage adius to adius to adius to adius to adius of Wheel adius of Axel 12 in.5 in 24 Consider an axle used to drive the wheels of a car. The wheel radius is 12 inches, while the axle radius is 1 inch. What is the mechanical advantage? You need to know the Circumference of Wheel C (Π)Wheel Diameter (3.14)D S Distance traveled in one revolu+on adius to adius to adius of Axle adius of Wheel 1in 12 in S 6

If your car has +res with a diameter of 24

28 X. S Distance traveled in one revolu+on 6.

9 revolu+ons Work at end Work at end () Dist.

moved by The number of strands suppor+ng the

7 If your car has +res with a diameter of 24 inches how many +mes will the +res rotate if the car travels 100 feet? 24 inches 2 feet C (Π)Wheel Diameter (3.14)2 X 6.28 X. S Distance traveled in one revolu+on 6.28 X Number of evolu+ons 100 X 6.28 X 15.9 revolu+ons Work at end Work at end () Dist. traveled by rope () Dist. moved by The number of strands suppor+ng the load. (The end strand ONY counts when the effort is poin+ng upward.) Fixed Pulley 1 Movable Pulley 2 Block & Tackle 4 7

# of strands 6 6 10 lb 60 lb Distance traveled 2 X * 6 Distance traveled 12 X or

8 The pulley system shown is used to lix a load of 60 lbs a distance of 2. ow much effort must be applied, and how much rope do you need to pull? # of strands lb 60 lb Distance traveled 2 X * 6 Distance traveled 12 X or or The is parallel to the Inclined Plane. The is 90 0 to the ground. Or in the direc+on of gravity. 8

or ength of Inclined Plane The ength is how long the Inclined

or eight of Inclined Plane The eight is ver+cal distance between

In the diagram below, 24 inches, 6 inches and the 60 lb Find the

What is the tradeoff for reducing the effort?

9 or ength of Inclined Plane The ength is how long the Inclined Plane is. or eight of Inclined Plane The eight is ver+cal distance between the star+ng point and ending point. In the diagram below, 24 inches, 6 inches and the 60 lb Find the mechanical advantage and the maximum load that can be moved. What is the tradeoff for reducing the effort? A θ B 24 in 4 6 in Mechanical Advantage B 4 30 lb 120 lb In order to move the 120 lb 6 inches off the ground, we need to travel a distance of 24 inches along the incline. A θ 9

10 Single Double Inclined Plane Wedge Mechanical Advantage Find the mechanical advantage and the maximum separa+on load for a wedge with an incline length of 10 inches, an overall height of 4 inches, and which is exer+ng an effort of 100 pounds. 10 in 4 in The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. estart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Mechanical Advantage lb 250 lb 10

11 1/4-20 UNC 1/4 the outer diameter of the threads. 20 the number of threads per inch of screw length. UNC refers to Unified Na+onal Coarse thread. OD Number of Threads per Inch Pitch Number of Threads per Inch 1in. View A 1in. View A Pitch 11

12 Mechanical Advantage A screw with 18 threads per inch is turned by a screwdriver having a handle diameter of 1 inch. What is the mechanical advantage of the screw? Circumference Pitch C P Circumference Pitch C P Circumference (3.14) 1 in 3.14 in Pitch 1 in in Circumference Pitch C P 3.14 in in

POE Review for Test 1 (Unit 1.1 Mechanisms and 1.2 -Energy)

Name: Period: POE Review for Test 1 (Unit 1.1 Mechanisms and 1.2 -Energy) Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Study the gear train in Figure