Mechanics Flashcards

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1
Q

Define distance

A

The physical distance between two points

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2
Q

Define displacement

A

The distance travelled in a certain direction

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3
Q

Define speed

A

The rate of change of distance with time

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4
Q

Define velocity

A

The rate of change of displacement with time and must include direction

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5
Q

State the formula, with the correct SI units, for speed and velocity

A

v = s/t

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6
Q

State the formula for average speed

A

Average speed = Total distance/Total time

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7
Q

Define acceleration

A

The increase in velocity of a body

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8
Q

State the formula, with the correct SI units, used to calculate acceleration

A

a = v/t

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9
Q

State what is calculated when the area under a velocity/time graph is calculated

A

Distance

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10
Q

Distinguish between mass and weight

A

Mass refers to the amount of matter in an object, while weight refers to the amount of gravitional pull that the earth exerts on an object

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11
Q

State the formula for weight, using the correct SI units

A

w = m x g

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12
Q

Define inertia

A

The property of matter to resist change unless acted upon by an external force

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13
Q

State why it is important to wear seatbelts when travelling, referring to inertia

A

Seatbelts act against inertia, protecting a person from colliding with someting incase of a sudden change in speed, for example in the case of a car accident

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14
Q

Define a force

A

A push or a pull exerted on an object

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15
Q

Name four effects that a force can have on an object

A
  • Change in size or shape
  • An object can break
  • The motion of an object can be changed
  • The position of an object can be changed
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16
Q

Define friction

A

The force that opposes relative motion

17
Q

Name the three factors on which the amount of friction between to objects depends

A
  • The type of surface the object is moving on
  • The amount of surface area of the object exposed to the surface
  • The weight of the object
18
Q

State four ways in which friciton can be reduced

A
  • A decrease in mass
  • Use rollers
  • Use smooth, hard surfaces
  • Use lubricants
19
Q

Define work

A

When a force causes an object to move in the direction of the applied force, work is done on the object

20
Q

Give the formula used to calculate the work done on an object

A

W = F x s

21
Q

True or false: Simple machines reduce the amount of work needed to be done on an object. If false, elaborate on you answer

A

False.
The work needed to be done on the object stays the same, but simple machines reduce the force required becomes less. They therefore make the work easier

22
Q

Define a lever

A

Simple rod pivoting around a falcrum. The object on which work is needed to be done is called the load and the force applied onto the lever is called the effort

23
Q

State why pulleys move when the rope around them is pulled

A

Friction between the pulley and the rope causes the pulley to move with the rope

24
Q

State the law of conversion of energy

A

Energy cannot be created or destroyed, it can only be changed from one form into another and transfered from one object onto another

25
Q

State the formula for calculating the efficiency of a simple machine

A

Work done on load/work done by effort

26
Q

Name 7 renewable resources of energy

A
  • Solar power
  • Wind power
  • Hydro-electric power
  • Tidal energy
  • Biomass
  • Geothermal power
  • Wave power
27
Q

State 3 advantages and 3 disadvantages of solar energy

A

Advantages:

  • Renewable
  • No pollutants or waste products
  • Converts solar energy directly to electrical energy

Disadvantages:

  • Low efficiency
  • High initial cost
  • Limited use in areas with limited sunshine
28
Q

Outline two uses of a solar furnace

A
  • Metal ore extraction

- Solar cooker

29
Q

State 3 advantages and 3 disadvantages of wind energy

A

Advantages:

  • Renewable
  • No pollutants or waste products
  • Low-level technology required

Disadvantages:

  • Scenic pollution
  • Windy site is essential
  • Unreliable due to varying in wind
30
Q

State 3 advantages and 3 disadvantages of hydro-electric energy

A

Advantages:

  • Renewable
  • No pollutants or waste products
  • Dam water can be used for irrigation

Disadvantages:

  • Limited number of usable sites
  • High initial cost
  • Initial disturbance of ecology
31
Q

State 2 advantages and 3 disadvantages of wave energy

A

Advantages:

  • Renewable
  • No pollutants or waste products

Disadvantages:

  • Insufficient capture of energy
  • Visual pollution
  • High maintenance
32
Q

State 2 advantages and 1 disadvantages of biomass

A

Advantages:

  • Renewable
  • Low level of technology required

Disadvantages:
- Not suitable for the generation of electricity

33
Q

State 1 advantages and 3 disadvantages of geothermal power

A

Advantages:
- Renewable

Disadvantages:

  • Limited number of suitable sites
  • High cost of drilling
  • Danger of radioactive gases
34
Q

State 1 advantages and 3 disadvantages of tidal power

A

Advantages:
- Renewable

Disadvantages:

  • Limited number of suitable sites
  • High cost in building
  • Initial disturbance of ecology
35
Q

State the formula used to calculate kinetic energy

A

Ek = 1/2mv(sqaured)

36
Q

State the formula used to calculate potential energy

A

Ep = mgh