1.1.2.A Simple Machines Practice Problems PDF

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Sketches are all the way at the bottom Activity 1.1.2 Simple Machines Practice Procedure Answer the following questions regarding simple machine systems. Each question requires proper illustration and annotation, including labeling of forces, distances, direction, and unknown values. Illustrations should consist of basic simple machine functional sketches rather than realistic pictorials. Be sure to document all solution steps and use proper units. All problem calculations should assume ideal conditions and no friction loss. Simple Machines – Lever A first class lever in static equilibrium has a 50 lb resistance force and 15 lb effort force. The lever’s effort force is located 4 ft from the fulcrum. 1. Sketch and annotate the lever system described above. 2. What is the actual mechanical advantage of the system? ula Ama=fr/fe

Substitute / Sol 50/15

Final Answer

3.3

50 lb 15lb 3. Using static equilibrium calculations, calculate the length from the fulcrum to the resistance force. 4ft Formula Ama=ima Fr/fe=de/dr

Substitute / Solve 50lb x dr =15 x 4 Dr=60 x lb/50

Final Answer

1.2 ft 60 divided by 50

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 1

A wheel barrow is used to lift a 200 lb load. The length from the wheel axle to the center of the load is 2 ft. The length from the wheel and axle to the effort is 5 ft. 4. Illustrate and annotate the lever system described above.

5. What is the ideal mechanical advantage of the system? Formula

Substitute / Solve

Final Answer

Ima=de/dr

Ima=5/2

2.5ft

6. Using static equilibrium calculations, calculate the effort force needed to overcome the resistance force in the system. Formula Mr=me Fr dr=fe de

Substitute / Solve 200 x 2=fe 5 Fe=200 x 2/5 400/2

Final Answer 80

A medical technician uses a pair of four-inch-long tweezers to remove a wood splinter from a patient. The technician is applying 1 lb of squeezing force to the tweezers. If more than 1/5 lb of force is applied to the splinter, it will break and become difficult to remove. 7. Sketch and annotate the lever system described above.

8. What is the actual mechanical advantage of the system? Formula

Substitute / Solve

Final Answer

Ama=fr/fe

1/5/1

0.2

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 2

9. Using static equilibrium calculations, calculate how far from the fulcrum the tweezers must be held to avoid damaging the splinter. Formula Mr=me Fr dr = fe de

Substitute / Solve 0.2 x4 = 1 de De= 0.2 x 4/1 0.8/1

Final Answer 0.8

Simple Machines – Wheel and Axle 10. What is the linear distance traveled in one revolution of a 36-in diameter wheel? Formula

Substitute / Solve

Final Answer

C=pie x d

C= pie x 36

113

An industrial water shutoff valve is designed to operate with 30 lb of effort force. The valve will encounter 200 lb of resistance force applied to a 1.5 in. diameter axle. 11. Sketch and annotate the wheel and axle system described above.

12. What is the required actual mechanical advantage of the system? Formula

Substitute / Solve

Final Answer

Ama=fr/fe

200/30

6.6

13. What is the required wheel diameter to overcome the resistance force? Formula Mr=me Fe de =fr dr

Substitute / Solve 30 de = 200x1.5 De= 200x1.5/30 300/30

Final Answer 10

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 3

Simple Machines – Pulley System A construction crew lifts approximately 560 lb of material several times during a day from a flatbed truck to a 32 ft rooftop. A block and tackle system with 50 lb of effort force is designed to lift the materials. 14. What is the required actual mechanical advantage? Formula

Substitute / Solve

Ama=fr/fe

Ama=560 lb/50

Final Answer 11.2

15. How many supporting strands will be needed in the pulley system? Formula

Substitute / Solve

Final Answer

Ima= number of strands

11.2 round

12

A block and tackle system with nine supporting strands is used to lift a metal lathe in a manufacturing facility. The motor being used to wind the cable in the pulley system can provide 100 lb of force. 16. What is the mechanical advantage of the system? Formula

Substitute / Solve

Final Answer

Ima = number of strands

9

9

17. What is the maximum weight of the lathe? Formula

Substitute / Solve

Ima=am Fr/fe

9=fr/100

Final Answer Fr=900

Simple Machines – Inclined Plane A civil engineer must design a wheelchair-accessible ramp next to a set of steps leading up to a building. The height from the ground to the top of the stairs is 2 ft. Based on ADA codes, the slope must be 1:12 or less. Slope is equal to the rise of the ramp divided by the run of the ramp. 18. Sketch and annotate the inclined plane described above.

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 4

19. base?

Using the ADA code, what is the minimum allowable length of the ramp Formula

Substitute / Solve 1/12=2/x x=2/1/12

Final Answer X=24

slope Divide 2 by 1/12 and it gives you 24

20. Using the known height and calculated base length, what is the length of the slope of the ramp? Formula

A2+b2=c2

Substitute / Solve C2=(2)^2+(24)^2 4+576 580^2=c^2 Square root 24.1

Final Answer

24.1

21. What is the ideal mechanical advantage of the ramp? Formula

Substitute / Solve

Final Answer

22. If a person and wheelchair have a combined weight of 185 lb, how much ideal effort force is required to travel up the ramp? Formula

Substitute / Solve

Final Answer

Ima=de/dr=l/h

24/2

12

Simple Machines – Wedge Hydraulic shears are used in manufacturing to cut large sheets of metal. Using hydraulic pressure, the machine pushes a wedge that is shaped as an inclined plane —not biface like an axe—to cut the metal. (Imagine one side or blade of a pair of scissors.) In this problem, a shear has a ¼-inch thick cutting blade with a 45-degree slope between the two sides of the blade. Hydraulic pressure applies a 2000-lb force to a wedge. 23. Sketch and annotate the cross-section of the wedge described above.

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 5

24.

What is the length of the slope? Formula A2+b2=c2

Substitute / Solve .25^2+.25^2 0.125=c^2 0.35355

Final Answer . 0.35355

25. What is the ideal mechanical advantage of the wedge? Formula

Substitute / Solve

Final Answer

Ima=de/dr=l/h

.25/.25

1

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 6

© 2012 Project Lead The Way, Inc. Principles of Engineering Activity 1.1.2 Simple Machines Practice Problems – Page 7

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