Pre-test Links, Guides, Motions and Materials

1. Drill presses used in technology workshops include a belt-and-pulley system that brings about a change in speed as motion is transmitted between the driver component and the driven component.

In which one of the following situations will the drill bit rotate fastest?

2. Which statement correctly explains the driver, driven and intermediate?A) The driver initiates the motion, the driven receives the motion and the

intermediate is in between the driver and the driven.B) The driver receives the motion, the driven initiates the motion and the

intermediate is in between the driven and the driven.C) The driver initiates the motion, the intermediate receives the motion and

the driven is in between the driver and the intermediate.D) The driver receives the motion, the driven initiates the motion and the

intermediate comes after the driven.

3. Should the following system be considered a motion transmission system or a motion transformation system?

4. Look at the three motion transmission systems below.

114 teeth 11117 teeth

14 teeth 7 teethIn which of these three systems does the biggest speed change occur?

A) System 1 because the diameter difference between the driver and the driven is greater than system 2 and 3.

B) System 2 because the diameter difference between the driver and the driven is greater than system 1 and 3.

C) System 3 because the diameter difference between the driver and the driven is lesser than system 1 and 2.

D) System 1 and 3 because the diameter difference between the driver and the driven is lesser than system 2.

5. Below, is a picture of a manual hand drill. When you rotate the crank, the mandrel will also rotate. Which answer best describes the drill?

A) The crank is the driver and the mandrel is the driven and it represents a motion transformation system.

B) The crank is the driven and the mandrel is the driver and it represents a motion transformation system.

C) The crank is the driver and the mandrel is the driven and it represents a motion transmission system.

D) The crank is the driven and the mandrel is the driver and it represents a motion transmission system.

6. Name each system below and state whether they perform a transmission system or transformation system.

7. Identify the type of guide in the pictures provided.

A) B) C)

8. The diagram below illustrates an automatic system simulating the flight of a butterfly that turns when you rotate a crank.To prevent the parts from slipping, what mechanism should replace the friction gears in this system?

A) Bevel gear C) Slider and crankB) Pulley and belt D) Cam and follower

Crank

9. An electric motor spins a 16-tooth gear in a clockwise fashion at the rate of 12 rotations per second.

You are working on a project and need to reduce the overall speed to 8 rotations per second clockwise. Four different gears are available: A, B, C, and D.

Gear A

8-tooth gear

Gear B

16-tooth gear

Gear C

24-tooth gear

Gear D

32-tooth gear

Describe how you would add gears to the motor gear in order to create an overall clockwise motion of 8 rotations per second.

Indicate the order in which the gears must be added, the direction of motion of each gear (clockwise or counter-clockwise) and the number of teeth on each gear.Justify your answer with calculations.

Use the appendix on the following page to help you answer questions 10-15

10. To move appropriately, subassembly B represented below needs a guiding control. Which part acts as the guiding control for this subassembly and what type of guiding is involved?

11. To move appropriately, subassembly A shown below needs a guiding control

a- Which part acts as the guiding control for this subassembly?

b- What type of guiding is involved?

12. a- When the memo holder is opened, to what mechanical constraint are its jaws subjected?

b- What mechanical property must the jaws have so that they can be subjected to this constraint?

13. a- To what constraint are the two ends of the clip subjected when the memo holder is opened?

b- What mechanical property must the clip have so that it can be subjected to this constraint?

14. The following are mechanical properties of materials.

- Hardness - Elasticity - Malleability - Stiffness - Resilience

What mechanical property must the clip have so that it can be subjected to this constraint when the memo holder is used? Explain why.

15. Circle the answers for the three links.

16. Match the constraint with its description with its exampleConstraint Description Example Draw symbol

A- Compression B- Tension C- Torsion D- DeflectionE- Shearing

17. What is the difference between thermoplastic and thermosetting?

18. During a violent storm, the windows of the “Three Little Pigs” boutique were broken by flying debris, nearly injuring its customers. As a result, the owners want to replace the glass in their windows with a transparent material that is more resistant. What mechanical properties must the transparent material have?

A) Elasticity and hardness C) Resilience and hardnessB) Elasticity and malleability D) Resilience and malleability

19. What is the motion transmission system and the motion transformation system shown below?

Transmission Transformation A Belt and pulley Rack and pinionB Belt and pulley Screw gearC Screw gear Worm and worm gearD Rack and pinion Screw gear

20. A circuit performer holds onto a twisted rope, maintaining the same position for a few seconds.

Which of the following choices indicates the two mechanical constraints to which the rope is subjected at the location where the arrow is pointing?

A) tension and compression C) deflection and torsionB) compression and deflection D) torsion and tension

21. A washing machine contains many parts that may break down over time. From the choices below, explain which would be the best system to attach the back cover of the machine to the body of the washing machine to permit access for repairs.

A) rivet B) glue (adhesive) C) screw D) nail

22. Gymnastics equipment is subjected to many constraints. Name each constraint for the following pictures.

A B C

For questions 23- 25 use the appendix on the last page.

23. Emily wants the hammers in her bicycle bell to turn faster. Her classmates have suggested four changes so that the clapper activating the hammers rotate faster. Choose the best answer which will allow the clapper in her bicycle bell to rotate faster.A) Increase the diameter of the hammers B) Reduce the number of teeth on the pinionC) Increase the diameter of the return springD) Make the clapper smaller

24. Using the picture below, indicate two components of the 5 listed needed to guide the rack and indicate the type of guiding control involved.

25. Give the links for the picture below. Write the answer below each section.