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Work and Machines Review Work Levers Inclined Power/ Your Planes Efficiency Teachers 100 100 100 100 100 200 200 200 200 200 300 300 300 300 300 400 400 400 400 400 500 500 500 500 500 Work for 100 What is the formula for work? Formula for work… Work = Force X Distance Work for 200 How much work is done if a a 50N force is applied on a stack of books to lift them 2m off the floor? Amount of work done… W=F X d = 50N X 2m = 100 J Work for 300… How much force is applied on a box if a person does 500J of work on the box for a distance 50m? Force applied… F= W / d = 500J / 50m = 10 N Work for 400 If you apply 20N of force upward on a flowerpot holding it up and walk a distance of 20m, how much work do your arms do on the flowerpot? The amount of work done… None! The flowerpot is not moving in the direction in which you are applying the force with your arms. Work for 500 You apply a force of 30N on a box you pick up off the floor and raise it up 5000mm off the floor. How much work did you do? The amount of work done… Work = Force X Distance = 30N X 5m = 150J Conversion: 5000mm = 5m Levers for 100 What other two simple machines can be classified as modified levers? The two simple machines are… Pulleys and Wheel & Axle Levers for 200 What is the IMA of the pulley system below? The IMA is… Number of strings minus 1 7-1 =6 Levers for 300 Label the diagram below with, Fe, de, Fr, and dr. Identify the class. Labeled and Class… Third Class dr Fr de Fulcrum Fe Levers for 400 What is the IMA of a wheel and axle that has a wheel with a radius of 20cm and an axle with a diameter of 10cm? The IMA is… IMA = rw / ra = 20cm / 5cm =4 Conversion: 10cm/2 = 5cm Levers for 500 Solve for the resistance distance. The resistance force is… Win = Wout Fe x de = Fr xdr 100N x 8m = 400N xdr 800Nm/400N = dr 2m = dr Inclined Planes for 100 What other two simple machines can be classified as modified Inclined Planes? The two simple Machines… Screw and Wedge Inclined Planes for 200 Which Screw has a higher IMA? A B More IMA… “B” has the highest IMA, because the threads are closer together. Inclined Planes for 300 What is the IMA of a knife with a length of 8cm and a thickness of 1cm? The IMA is… IMA = length/thickness = 8cm / 1cm = 8 Inclined Planes for 400 Label the diagram below with Fe, de, Fr, and dr. The labeled diagram… de dr Fe Fr Inclined Planes for 500 A ramp with a length of 5m and a height of 2m is used to a 600N rock on to a pickup truck. How much force will you have to exert on the rock to get it up the ramp (ideally)? The amount of force is… Win = Wout Fe x de = Fr x dr Fe x 5m = 600N x 2m Fe = 1200/5 = 240N Power/Efficiency for 100 What is the equation and units for power? The equation is… Power = Work Time Units in Watts(W) Power/Efficiency for 200 What is the formula and units for efficiency? The formula is… Efficiency= Workout x 100 Workin Units in percent (%) Power/Efficiency for 300 How do you increase the efficiency of a machine? You increase efficiency by… Adding oil or grease to decrease friction. Power/Efficiency for 400 How much work is done if 150W of power was used to move a 50N box in 10s? Work done… Power = Work / Time Work = Power x Time = 150W x 10s = 1500J Power/Efficiency for 500 You apply 50N of force to a lever for a distance of 3m. In return the lever puts out 100J of work. What is the efficiency of the lever? The efficiency is… Win = Fe x de = 50N x 3m = 150J Efficiency = Work out x 100 Work in =100J/150J x 100 = 66.67% Your Teachers for 100 Is Mr. Sebastian Married? Is Mrs. DeRiemaker Married? Married??? Mr. S. Yes Mrs. D. Yes Your Teachers 200 How many pets and types does Mrs. D have? Pets… Two Cats Your Teachers for 300 What College does Mr. S go to? College… MSU!!!! Go STATE! Your Teachers 400 What does Mr. S do to actually earn money? Hint: It is not working at Eisenhower Job… Milking Cows! Your Teachers 500 What month is Mrs. D’s baby due? Baby… April

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posted: | 6/29/2011 |

language: | English |

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