Engineering Unit: Grade 9 science IB Flashcards

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1
Q

What is a Mechanical Property?

A

A mechanical property determines how a material will react when it is subjected to one or more mechanical constraints.

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2
Q

List the types of Mechanical Properties:

A
  1. Hardness (resists penetration)
  2. Elasticity (returns to original shape)
  3. Resilience (resists physical impacts)
  4. Ductility (stretches without breaking)
  5. Malleability (flattens or bends without breaking)
  6. Tensile strength (resists tension, elastic)
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3
Q

What is a mechanical constraint?

A

A mechanical constraint describes the stress produced within a material when it is subjected to one or more external forces; mechanical constraints produce various effects inside a material.

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4
Q

List the 5 principle mechanical constraints:

A
  1. Compression (crushes materials)
  2. Tension (force that stretches materials)
  3. Torsion (force that twists materials)
  4. Bending (force that bends materials)
  5. Shearing (force that cuts/tears materials)
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5
Q

What are the 4 mechanical functions?

A
  • Link
  • Guide
  • Lubrication
  • Seal
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6
Q

Define a link:

A

Links are used to connect 2 or more parts of an object.

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7
Q

Define a guide:

A

Forces a part to follow a certain guiding motion (translation/rotation)

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8
Q

Definition of lubrication:

A

Reduces friction by technical means.

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9
Q

Definition of seal:

A

Prevents a gas or liquid from escaping.

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10
Q

Types of guiding:

A

Rotations, Translation, Helical

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11
Q

Gear Train:

A
  • Components of a gear train include and driver, and a follower, sometimes they also include intermediates.
  • In a gear train each gear turns opposite in direction to the gear(s) directly beside it
  • Reversible
  • Motion Transmission system: rotation - rotation
  • Should be lubricated
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12
Q

Chain and Sprocket systems:

A
  • Components of a chain and sprocket system include gears, and a chain .
  • In a chain and sprocket system gears within the train turn one way, and gears outsides the chain turn the opposite direction.
  • Reversible
  • Motion Transmission system: rotation - rotation
  • Should be lubricated
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12
Q

Chain and Sprocket systems:

A
  • Components of a chain and sprocket system include gears, and a chain .
  • In a chain and sprocket system gears within the train turn one way, and gears outsides the chain turn the opposite direction.
  • Reversible
  • Motion Transmission system: rotation - rotation
  • Should be lubricated
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13
Q

Friction gear system

A
  • Components of a friction gear system include and driver, and a follower, sometimes they also include intermediates.
  • In a friction gear system each gear turns opposite in direction to the gear(s) directly beside it
  • Reversible
  • Motion Transmission system: rotation - rotation
  • Should NOT be lubricated
  • Diameter = teeth (equivalent to gear train)
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14
Q

Belt and Pulley system

A
  • Components of a belt and pulley system include pulleys (gears without teeth), and a belt.
  • In a belt and pulley system pulleys within the belt turn one way, and pulleys outsides the belt turn the opposite direction.
  • Reversible
  • Motion Transmission a system: rotation - rotation
  • Should NOT be lubricated
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15
Q

Wheel and worm-wheel system

A
  • Components of a wheel and worm-wheel system include a worm-wheel (screw), whose rotation is transmitted to one or more wheels.
  • In a wheel and worm-wheel system both the wheel and worm-wheel both rotate in the same direction.
  • NOT reversible, the worm-wheel is ALWAYS the driver
  • Motion Transmission system: rotation - rotation
  • Should be lubricated
16
Q

Rack and Pinion system

A
  • Contains at least one gear called a pinion, and a straight, teethed bar called a rack,
  • Reversible
  • Motion Transformation System : Rotation - translation (& vice versa)
  • Should be lubricated
17
Q

Screw-Gear System

A
  • Contains a screw and a nut
  • Irreversible; nut rotates and transforms into the translational motion in the screw. The nut it always the driver
  • Motion Transformation System : Rotation - translation
  • Should be lubricated
18
Q

Cam and follower system

A
  • Contains a cam (egg shaped piece), and a follower (a stick that bobs).
  • NOT Reversible, Cam is ALWAYS driver
    *Follower follows…lol…. It is driven.
  • Cam rotates, Follower translates
  • Motion Transformation System : Rotation - translation
  • Should NOT be lubricated
19
Q

Slider-crank mechanism

A
  • Contains a crank, slider, and guide.
  • Reversible, crank and slider can switch which is driver/driven
  • Crank rotates like wheels, slider translates like a piston
  • Motion Transformation System : Rotation - translation (& vice versa)
  • Should be lubricated
20
Q

Speed Change!

A

Increase: Driver is bigger/has more teeth than driven
Decrease: Driven is smaller/has less teeth than driven
No Change: Driver and driven are the same in size/teeth

21
Q

Define exploded view

A

Shows all components of an object separated from each other.