Notes & theory for this topic

Units

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1. Calculate the following conversions, giving your answers to 3 significant figures. Remember to add the units.
  1. How many kg are there in 2 lb?
    Show answer
    1 lb = 0.4536 kg
    2 lb = 0.907 kg
  2. How many l are there in 3 pt?
    Show answer
    1 pt = 0.5683 l
    3 pt = 1.70 l
  3. How many km are there in 2 mile?
    Show answer
    1 mile = 1.6093 km
    2 mile = 3.22 km
  4. How many mm are there in 7 in?
    Show answer
    1 in = 25.4 mm
    7 in = 178 mm
2. Calculate the following conversions, giving your answers to 3 significant figures. Remember to add the units.
  1. How many gal are there in 130 l?
    Show answer
    1 l = 0.22 gal
    130 l = 28.6 gal
  2. How many mile are there in 9 km?
    Show answer
    1 km = 0.6214 mile
    9 km = 5.59 mile
  3. How many ft are there in 120 mm?
    Show answer
    1 mm = 0.00328 ft
    120 mm = 0.394 ft
  4. How many lb are there in 6 kg?
    Show answer
    1 kg = 2.2046 lb
    6 kg = 13.2 lb
3. Calculate the following, giving your answers to 3 significant figures. Remember to add the units.
  1. How many square millimetres (mm2) are there in a square of side 60 mm?
    Show answer
    area = 60 mm × 60 mm
    3600 mm2
  2. How many litres (l) are there in 1 cubic metres (m3)?
    Show answer
    1 m3 = 1000 l
    1000 l
  3. What is the mass (kg) of 7 litres of water?
    Show answer
    1 litre of water has a mass of 1 kg
    7.00 kg
  4. What is the mass (g) of 3 centilitres of water?
    Show answer
    1 centilitre of water has a mass of 10 g
    30.0 g
4. Calculate the following speed conversions, giving your answers to 3 significant figures. Remember to add the units.
  1. How many m/s are there in 4000 km/hr?
    Show answer
    1 km/hr = 0.2778 m/s
    4000 km/hr = 1110 m/s
  2. How many m/s are there in 40 mph?
    Show answer
    1 mph = 0.447 m/s
    40 mph = 17.9 m/s
  3. How many m/s are there in 5000 ft/s?
    Show answer
    1 ft/s = 0.3048 m/s
    5000 ft/s = 1520 m/s
  4. How many m/s are there in 20 in/s?
    Show answer
    1 in/s = 0.0254 m/s
    20 in/s = 0.508 m/s
5. Write the following numbers to the specified number of significant figures.
  1. Write 0.0000123 to 4 significant figures.
    Show answer
    0.00001230
  2. Write 0.000761 to 2 significant figures.
    Show answer
    0.00076
  3. Write 144.777 to 2 significant figures.
    Show answer
    140
  4. Write 13900900 to 5 significant figures.
    Show answer
    13901000
6. Give the following numbers in scientific notation. Write 1.23 × 104 as 1.23E4. Do not change the number of significant figures.
  1. Write 0.00101 in scientific notation.
    Show answer
    1.01E-3
  2. Write 7203.3 in scientific notation.
    Show answer
    7.2033E3
  3. Write 737060 in scientific notation.
    Show answer
    7.37060E5
  4. Write 3568300 in scientific notation.
    Show answer
    3.568300E6
7. Give the following numbers in engineering notation (the exponent is a multiple of 3). Write 1.23 × 104 as 1.23E4. Do not change the number of significant figures.
  1. Write 141.31 in engineering notation.
    Show answer
    141.31E0
  2. Write 0.00349 in engineering notation.
    Show answer
    3.49E-3
  3. Write 7218.4 in engineering notation.
    Show answer
    7.2184E3
  4. Write 0.01387 in engineering notation.
    Show answer
    13.87E-3
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