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Science 8 > Mechanical Systems Unit Exam > Flashcards

Mechanical Systems Unit Exam Flashcards

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1
Q

What is a machine?

A

A device that helps us do work.

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2
Q

Name one example of an early machine that depended on a person and an animal to do the work.

A

A Plow.

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3
Q

What were Roman Aqueducts? How were they used?

A

Roman aqueducts were how early civilizations got water to their homes. They were used for transporting water for many kilometres to supply cities.
They used pumps (to raise water into reservoirs) and channels (on a slope to carry the water), and had a distribution system (distributes water within a city).

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4
Q

What is a Sakia? How was it used?

A

It was lots of buckets attached to a long rope draped over a wheel.
The wheel is turned by animals, which raises the buckets of water.

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5
Q

What is an Archimedes Screw? How was it used?

A

It’s a giant screw with grooves inside.

The screw picks up the water and carries it up to the top of the tube with the grooves as it turns.

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6
Q

What is a simple machine?

A

a tool or device made up of one basic machine.

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7
Q

What are the 6 simple machines?

A

Wheel and axel, screw, lever, wedge, inclined plane, pulley

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8
Q

Name 3 factors of the lever.

A
  1. It’s a rigid bar or plank that rotates around a pivot or fulcrum.
  2. Enables the user to move a larger load than without.
  3. The user must move a greater distance than the load.
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9
Q

What are the 3 types of levers?

A

First class, second class, third class.

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10
Q

What is a first class lever?

A

⬇️effort ……………………………………………⬇️Load
————————————————————
…………………………🔼fulcrum

Fulcrum is between the downward forces of the effort and load

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11
Q

What is a second class lever?

A

………..Load⬇️ ………………………. ⬆️effort
————————————————————
🔼fulcrum

Downward force of the load is in between the fulcrum and upward force of the effort.

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12
Q

What is a third class lever?

A

…………Effort⬆️ …………………… ⬇️load
————————————————————
🔼fulcrum

Upward force of the effort is in between the fulcrum and the downward force of the load.

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13
Q

Name 4 factors of the inclined plane, and provide an example.

A
  1. It’s a flat surface that is at an angle to another flat surface, such as the ground.
  2. Enables the user to move a larger load than without.
  3. But the user must move a greater distance than the load.
  4. The ramp can’t be too steep or it won’t work.
    Ex: A ramp
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14
Q

Name 5 factors of the wedge, and provide an example.

A
  1. Similar to the inclined plane, but is forced into an object.
  2. By pressing on the wide end, the narrow end splits the object.
  3. Can only be used in one direction, to push objects apart.
  4. Enables the user to apply a greater force on the object.
  5. But the user must move a greater distance than the split.
    Ex: an axe
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15
Q

Name 4 factors of the screw.

A
  1. Consists of a cylinder with a groove cut in a spiral on the outside.
  2. Can penetrate materials using a relatively small force.
  3. Convert rotational motion to linear motion.
  4. Most screws move objects very slowly.
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16
Q

Name 3 factors of the pulley, and give an example.

A
  1. Made up of a wire, rope, or cable moving on a grooved wheel.
  2. May be made up of one or many wheels.
  3. Can be fixed in place or movable.
    Ex: how stage curtains rise.
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17
Q

Name 5 factors of a wheel and axel, and give an example.

A
  1. Made up of two wheels of different diameters the turn together.
  2. A longer motion on the wheel produces a shorter more powerful motion on axle.
  3. Enables the user to apply a greater force on an object.
  4. But the user must move the wheel a greater distance to apply the force.
  5. Can also be used to increase speed (ex: bicycle)
    Ex: Wheels on a car
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18
Q

What is a complex machine?

A

A system in which simple machines all work together.

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19
Q

What is a system?

A

A group of parts that work together to perform a function.

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20
Q

What is a subsystem?

A

A smaller group of parts in a complex machine with one function.
Ex: Braking
Steering

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21
Q

What are 2 subsystems that transfer forces?

A

Linkage and transmission.

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22
Q

What is linkage?

A

A belt or chain to transfer energy from a energy source to an object.
Ex: Bicycle chain

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23
Q

What is transmission?

A

A special type of linkage for transferring energy from the engine to the wheel in large vehicles such as cars or trucks.
More useful when larger loads must be moved.

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24
Q

Name 3 factors of gears.

A
  1. They’re a pair of wheels with teeth that interlink When they rotate together, one gearwheel transfers turning motion and force to the other.
  2. They’re important because they control the transfer of energy in a system.
  3. Gear wheels work together in gear trains (2 or more gears).
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25
Q

What is the driving gear?

A

The gear that has the original force applied to it.

26
Q

What is the driven gear?

A

The gear that receives the force after.

27
Q

What happens when the driving gear is smaller than the driven gear?

A

The turning speed in the system increases.

28
Q

What is it called when the driving gear is smaller than the driven gear?

A

Multiplying gears.

29
Q

Name 1 fact about multiplying gears.

A

For every turn the larger wheel makes the smaller gear will do many more

30
Q

What happens when the driving gear is larger than the driven gear?

A

The turning speed in the system decreases.

31
Q

What is it called when the driving gear is larger than the driven gear?

A

Reducing gears.

32
Q

Name 1 fact about reducing gears.

A

In some systems the gears are meshed together, but in some cases they are
connected by a linkage.

33
Q

What is Mechanical Advantage?

A

The amount by which a machine can multiply a force.

34
Q

What is Input Force?

A

The force applied to the machine.

35
Q

What is Output Force?

A

The force the machine applies to the object.

36
Q

What does Speed do?

A

It measures the distance an object travels in a given amount of time.

37
Q

What is Speed Ratio?

A

The measure of how the speed of the object is affected by a machine.
It describes how much faster the user is moving than the load is working.

38
Q

What is a Mechanical Advantage less than 1 useful for?

A

Its useful for tasks that do not require a large output force.
Ex: Bicycle — the output force is used for speed.

39
Q

What is friction?

A

A force that opposes motion.

40
Q

What is Efficiency?

A

The measurement of how well a machine or device uses energy.

41
Q

What does MA equal for pulleys?

A

Output distance / input distance

42
Q

What does MA equal for inclined planes?

A

Hypotenuse (length) / height

43
Q

What does MA equal for levers?

A

Effort arm / load arm

44
Q

What is work?

A

Done when a force acts on an object to make the object move.
Movement is needed before you can say that work has been done!
No movement = no work

45
Q

What are the 2 things the amount of work depends on?

A
  1. The amount of force exerted on the object.

2. Distance the object moved in the direction of the applied force.

46
Q

What is work/energy measured in?

A

Joules (J)

47
Q

What is a Hydraulic System?

A

A system that uses a liquid under pressure to move loads.

48
Q

What is Pascal’s Law?

A

Pressure applied to an enclosed fluid is transmitted equally in all directions.

49
Q

How do hydraulic systems work?

A

Pistons.

50
Q

What are pistons?

A

Disks that fit tightly inside a cylinder.

As the disk moves it either pushes fluid out or draws a fluid in.

51
Q

What pistons are used in hydraulic systems?

A

A hydraulic system is a combination of 2 pistons attached by a flexible pipe.
Input Piston – used to apply force to the fluid.
Output Piston – transfers the force to the load

52
Q

What provides the MA in a hydraulic system?

A

Pascals Law

53
Q

How are designs evaluated?

A

They are evaluated qualitatively and quantitatively using the following criteria:

  1. Efficiency and Effectiveness
  2. Function and Design
  3. Environmental Impact
  4. Cost
54
Q

What does qualitative mean?

A

A description or category used to classify how efficient a machine is.
Ex: This machine helps you complete the task more quickly

55
Q

What does quantitative mean?

A

The numerical value of how efficient a machine is.

Ex: The machine is 45% efficient

56
Q

What does function mean?

A

The purpose of the machine.

57
Q

What does design mean?

A

The physical form of the design.

58
Q

What are 2 ECONOMIC things to consider when building a machine?

A
  1. How much are the materials?

2. Is it $$$ to run (ex. Fuel costs)?

59
Q

What are 3 ENVIRONMENTAL things to consider when building a machine?

A
  1. Does it give off emission?
  2. Does it need a lot of land to build?
  3. How much waste is made to develop it?
60
Q

What are 3 SOCIAL things to consider when building a machine?

A
  1. Does it provide or take away jobs?
  2. Are the workers being treated fairly?
  3. Is fair trade occurring to share and get resources used in production?

Science 8 (3 decks)

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