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Marking the Mechanical Systems Quiz II

Marking the Mechanical Systems Quiz II. Put your name down as the marker at the top of the paper that you are marking Be sure to write in correct answers and make corrections to help the other person study for the upcoming quiz

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Marking the Mechanical Systems Quiz II

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  1. Marking the Mechanical Systems Quiz II

  2. Put your name down as the marker at the top of thepaperthat you are marking • Be sure to write in correct answers and make corrections to help the other person studyfor the upcoming quiz • Ask questions if you are unsure about an answer I have on the board… this is your chance to get feedback and to make sure you are on the tight track • PLEASE MAKE SURE YOU ARE KEEPING A TALLEY OF TOTAL MARKS IN THE MARGIN SO THAT I CAN SEE HOW YOU’RE DOING First Things First…

  3. FrictionD • EfficiencyI • Mechanical AdvantageG • Speed RatioH • WorkC • Input Force A • Output ForceF • Input Distance E • Output Distance B A This is the amount for energy that a person exerts on their end of the simple machine B This is the distance that the load covers when it is being moved by a simple machine C This is usually measured in joules and is the product of force and distance D All simple machines create some amount of ________________ which means our input force must be increased slightly to overcome it. E This is how far a person must exert a force over when using a simple machine F This is the amount of energy it takes to move a load or an object when there are no simple machines involved. G This calculated value will indicate how must a simple machine has multiplied a person’s input force H This calculated value will indicated how many times further a person had to apply their reduced force when using a simple machine I This calculated value will be directly affected by the amount of friction a simple machine creates. Questions 1… Matching • Total of 9 marks for this question

  4. Km hmDmmdm cm mm • 385 cm  ____m • 3 8 5 . = 3.85 m Questions 2 a) Convert all of the metric measurements shown below, back into “meters” 385 cm = 3.85 m (1 mark) Total of 1 mark for this question

  5. Km hmDmmdm cm mm • 5.67 Km  ____m • 5 . 6 7 0 = 5670 m Questions 2 b) Convert all of the metric measurements shown below, back into “meters” 5.67 Km = 5670 m (1 mark) Total of 1 mark for this question

  6. Km hmDmmdm cm mm • 891 mm  ____m • 0 . 8 9 1 = 0.891 m Questions 2 c) Convert all of the metric measurements shown below, back into “meters” 891 mm = 0.891 m (1 mark) Total of 1 mark for this question

  7. Question 3 In the case of the many simple machines, the trade-off is that we have a reduced our input force (1 mark) but we have to apply it over a longer distance (1 mark) We have used the term “You don’t get something for nothing” when talking about using simple machines. In one or two sentences, explain what a simple machine does to make our job easier and what the “Trade off” is (or cost to us) in return. • Total of 2 marks for this question

  8. MA = 2 Sketch Questions 4 a) MA = 1 Sketch 1 mark for having this pulley at the top 1 mark for having this pulley attached to the load • Total of 2 marks for this part of the question

  9. MA = 2 Sketch Questions 4 b) MA = 1 Sketch Type of Pulley - FIXED (1 mark) Type of Pulley - MOVEABLE (1 mark) • Total of 2 marks for this part of the question

  10. You are using a ramp to get a load of boxes into the back of a truck that is 1.5 m off the ground. The ramp is 8 m long. If you were to lift the load straight up into the truck, you would need to exert a force of 165 N. However, when you roll the load up the ramp, you only need to push with a force of 35 N. Please calculate the “Input Work” & “Output Work” for this simple machine. Question 6 a) • Input Force = 35 N (1 mark) • Output Force = 165 N (1 mark) • Input Distance = 8 m (1 mark) • Output Distance = 1.5 m (1 mark) • Total of 4 marks for this part of the question

  11. Total of 3 marks • 1 mark for the formula • 1 mark for the numbers • 1 mark for the answer • MUST HAVE UNITS… ½ off Question 5 b) Input Work Winput = Finput x Dinput(1 mark) Winput = 35 N x 8 m (1 mark) Winput = 280 J (1 mark) • Total of 3 marks for this part of the question

  12. Total of 3 marks • 1 mark for the formula • 1 mark for the numbers • 1 mark for the answer • MUST HAVE UNITS… ½ off Question 5 b) Output Work Woutput = Foutput x Doutput(1 mark) Woutput = 165 N x 1.5 m (1 mark) Woutput = 247.5 J (1 mark) • Total of 3 marks for this part of the question

  13. Input Force = 35 N • Output Force = 165 N • Mechanical Advantage • MA = Foutput(1 mark) • Finput • MA = 165 N(1 mark… ½ off if no units are present) • 35 N • MA = 4.71 (1 mark… ½ off if any units are there) Question 5 c) • Total of 3 marks for this part of the question

  14. Input Distance = 8.4 m • Output Distance = 4 m • Speed Ratio • SR = Dintput(1 mark) • Doutput • SR = 8 m (1 mark… ½ off if no units are present) • 1.5 m • SR = 5.33 (1 mark… ½ off if any units are there) Question 5 c) • Total of 3 marks for this part of the question

  15. MA = 4.71 • SR = 5.33 • Efficiency = MA x 100 (1 mark) • SR • Efficiency = 4.71 x 100 (1 mark) • 5.33 • Efficiency = 88.36 % (1 mark… ½ off if no % sign) Question 5 c) • Total of 3 marks for this part of the question

  16. Here you can see a man is using a class 1 leaver to help him lift up a large rock. The man must exert a force of 1240 N to lift the rock but the actual output force exerted on the rock is 7150 N. When the man pushes his end of the lever all of the way down he covers a distance of 2.3 m but the rock is only lifted 0.3 m off the ground. Calculate the input and output work done on the rock.. Question 6 a) • Input Force = 1240 N (1 mark) • Output Force = 7150 N (1 mark) • Input Distance = 2.3 m (1 mark) • Output Distance = 0.3 m (1 mark)

  17. Total of 3 marks • 1 mark for the formula • 1 mark for the numbers • 1 mark for the answer • MUST HAVE UNITS… ½ off Question 6 b) Input Work Winput = Finput x Dinput(1 mark) Winput = 1240 N x 2.3 m (1 mark) Winput = 2852 J (1 mark) • Total of 3 marks for this part of the question

  18. Total of 3 marks • 1 mark for the formula • 1 mark for the numbers • 1 mark for the answer • MUST HAVE UNITS… ½ off Question 6 b) Output Work Woutput = Foutput x Doutput(1 mark) Woutput = 7150 N x 0.3 m (1 mark) Woutput = 2145 J (1 mark) • Total of 3 marks for this part of the question

  19. Input Force = 1240 N • Output Force = 7150 N • Mechanical Advantage • MA = Foutput(1 mark) • Finput • MA = 7150 N(1 mark… ½ off if no units are present) • 1240 N • MA = 5.77 (1 mark… ½ off if any units are there) Question 6c) • Total of 3 marks for this part of the question

  20. Input Distance = 2.3 m • Output Distance = 0.3 m • Speed Ratio • SR = Dintput(1 mark) • Doutput • SR = 2.3 m (1 mark… ½ off if no units are present) • 0.3 m • SR = 7.67 (1 mark… ½ off if any units are there) Question 6c) • Total of 3 marks for this part of the question

  21. MA = 5.77 • SR = 7.67 • Efficiency = MA x 100 (1 mark) • SR • Efficiency = 5.77 x 100 (1 mark) • 7.67 • Efficiency = 75.23 % (1 mark… ½ off if no % sign) Question 6 c) • Total of 3 marks for this part of the question

  22. Explain why in the previous 2 questions the simple machines did not have an “Efficiency” of 100%... what caused the drop in efficiency? Simple machines will almost never have 100% efficiency because of FRICTION(1 mark) Friction will always cause some input energy to be lost which reduces the efficiency Question 7 a) • Total of 1 mark for this question

  23. If energy cannot be created or destroyed… where does all of the extra input energy go if a machine is less than 100% efficient? Does it just vanish or is it converted into a different form of energy? The extra energy put into overcoming friction is lost as HEAT ENERGY (1 mark) Friction causes heat Question 7 b) • Total of 1 mark for this question

  24. Below is a graph that displays the Input Force needed to roll a Jeep 5 m across a middle school soccer field. Study the graph and then use that data to answer the next 4 questions.  Question 8

  25. What would you predict the input force would be to move that jeep if you added a 5th pulley to the system and why? (use proper terminology) Question 8 a) 5th pulley A 5th pulley in the pulley system would be a FIXED PULLEY(1 mark)meaning it would not change the input force much… the input force would stay at about 305 N ± 10 N(1 mark) • Total of 2 marks for this question

  26. What would you predict the input force would be to move that jeep if you added a 6th pulley to the system and why? (use proper terminology) Question 8 b) 6th Pulley A 6th pulley in the pulley system would be a MOVEABLE PULLEY(1 mark)meaning it would cut the input force in half… the input force be reduced to about 155 N ± 10 N(1 mark) • Total of 2 marks for this question

  27. What would you predict the input force would be to move that jeep if you added a 7th pulley to the system and why? (use proper terminology) Question 8 c) 7th Pulley Again… a 7th pulley in the pulley system would be a FIXED PULLEY(1 mark)meaning it would not change the input force much… the input force would stay at about 155 N ± 10 N(1 mark) • Total of 2 marks for this question

  28. What would you predict the input force would be to move that jeep if you added a 8th pulley to the system and why? (use proper terminology) Question 8 d) 8th Pulley A 8th pulley in the pulley system would be a MOVEABLE PULLEY(1 mark)meaning it would cut the input force in half… the input force be reduced to about 80 ± 10 N(1 mark) • Total of 2 marks for this question

  29. Look at the wheel and axle combination in the picture to the right. Using the information you see there, create a formula and use it to calculate the Mechanical Advantage of the Wheel & Axle. Bonus Question 1 Mechanical Advantage MA = R of wheel ÷ rof axle(1 mark for the formula) MA = 96 cm ÷ 6 cm (1 mark… with units!!) MA = 16 (1 mark… without any units!!) • Total of 3 marks for this question

  30. Look at the picture of the lever to the right. Using the information you see there, create a formula and use it to calculate the Mechanical Advantage of the lever. Bonus Question 2 Mechanical Advantage MA = d from effort ÷d from load(1 mark for the formula) MA = 45 cm ÷ 15 cm (1 mark… with units!!) MA = 3 (1 mark… without any units!!) • Total of 3 marks for this question

  31. The total for this Quiz is /66 (+ 6 bonus marks)

  32. Total up the marks & write it down at the top of the front page along with the %… Please add these marks into your marks record Sheet Make sure you come in for extra help if you had troubles on this quiz Make sure that you guys are studying for these quizzes and using a cheat sheet… it will pay off!!

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