The Technological World

Question 1

What are the four characteristics used to describe a mechanical link?

Answer 1

1. Direct or indirect
2. Rigid or flexible
3. Removable or permanent 4. Complete or partial

Question 2

What type of link is created using a screw on glasses?

Answer 2

Removable, indirect, partial, rigid.

Question 3

What are the characteristics of the link in a glued bookshelf?

Answer 3

Indirect, complete, permanent, rigid.

Question 4

What is the function of guiding in a technical object?

Answer 4

To control the motion of a moving component so that it follows a specific trajectory.

Question 5

What are the three types of guiding?

Answer 5

Translational, rotational, helical.

Question 6

What guiding is used in a C-clamp?

Answer 6

Helical guidance.

Question 7

What guiding is used in a sliding window?

Answer 7

Translational.

Question 8

What is the function of a motion transmission system?

Answer 8

To transfer the same type of motion from one part to another (e.g. rotation to rotation).

Question 9

Name 5 types of motion transmission systems.

Answer 9

Friction gears, pulley and belt, gear assembly, sprockets and chain, wheel and worm gear.

Question 10

Is a wheel and worm gear reversible?

Answer 10

No, it’s irreversible.

Question 11

Why are sprockets and chains used in bikes instead of pulleys?

Answer 11

Because they don’t slip and can handle greater forces from pedaling.

Question 12

What is the direction of rotation in a friction gear system?

Answer 12

Opposite in each connecting gear.

Question 13

Name one disadvantage of friction gears.

Answer 13

They can slip and must stay clean.

Question 14

Which transmission system allows for the most force and least slippage?

Answer 14

Gear assemblies and sprocket/chain systems.

Question 15

Which gear turns faster: small or large?

Answer 15

The smaller gear turns faster.

Question 16

How do you increase the speed in a transmission system?

Answer 16

Use a smaller driver gear or fewer gear teeth.

Question 17

What is the formula for speed ratio?

Answer 17

Speed Ratio = Number of teeth on driven / Number of teeth on driver.

Question 18

What is a motion transformation system?

Answer 18

A system that changes the type of motion from one form to another (e.g. rotation to translation).

Question 19

Name 5 motion transformation systems.

Answer 19

Screw gear system, cam and follower, connecting rod and crank, rotating slider crank, rack-and-pinion.

Question 20

Which transformation systems are reversible?

Answer 20

Connecting rod and crank, lever and slide, rotating slider crank.

Question 21

What is the purpose of a cam and follower?

Answer 21

To produce precise, customized translational motion.

Question 22

Why is the screw gear system irreversible?

Answer 22

Because rotation transforms into translation, but not the other way around.

Question 23

What are 4 types of power supplies?

Answer 23

Battery (chemical), solar cell (light), piezoelectric (mechanical), thermocouple (heat), alternator (mechanical).

Question 24

What is the role of a power supply in a circuit?

Answer 24

To provide electrical current.

Question 25

Does a toaster use a battery as a power supply?

Answer 25

No, it uses a wall outlet (AC power).

Question 26

What is conduction?

Answer 26

The flow of electrons through a conductor.

Question 27

Name 3 conductors and 3 insulators.

Answer 27

Conductors: metal, electrolytic solution, copper. Insulators: plastic, rubber, glass.

Question 28

Why must wires connect to the metal part of a switch?

Answer 28

Because plastic is an insulator and won’t allow current to flow.

Question 29

What is the function of a switch in a circuit?

Answer 29

To control the flow of electricity by opening or closing the circuit.

Question 30

What type of energy transformation occurs in a toaster?

Answer 30

Electrical → thermal + mechanical + light.

Question 31

What energy transformation happens in a motor?

Answer 31

Electrical → mechanical + sound + heat.

Question 32

What energy transformation happens in a solar panel?

Answer 32

Light → electrical.

Question 33

What are the 5 types of external constraints?

Answer 33

Tension, compression, torsion, deflection, shearing.

Question 34

What is deflection?

Answer 34

A force that bends a material.

Question 35

Define resilience.

Answer 35

The ability of a material to absorb shock and return to its original shape.

Question 36

Define ductility and malleability.

Answer 36

Ductility: can be drawn into wires. Malleability: can be bent/flattened without breaking.

Question 37

What property means a material doesn’t react chemically?

Answer 37

Chemical neutrality.

Question 38

What property means it resists corrosion like rust?

Answer 38

Corrosion resistance.

Question 39

What are 3 properties needed in a hard-hat?

Answer 39

Hardness, resilience, stiffness.

Question 40

What is the difference between thermoplastics and thermosetting plastics?

Answer 40

Thermoplastics can be reshaped when heated, thermosetting plastics cannot.

Question 41

Give 3 properties of ceramics.

Answer 41

Hardness, heat resistance, low electrical conductivity.

Question 42

Why are thermosetting plastics used for cooking pot handles?

Answer 42

They retain shape and resist heat.

Question 43

How do you prevent wood from degrading?

Answer 43

Use varnish, paint, or chemical treatments.

Question 44

How do you protect metals?

Answer 44

Use metallic coatings (zinc, chrome), paint, or grease.

Question 45

What can be added to plastics to prevent UV damage?

Answer 45

Pigments that absorb UV rays and antioxidants like carbon.