4.1 Weight and Mass

Mass and weight are different. Mass is the measure of how much matter an object has. Weight depends on mass and the value of gravity. The units of mass and weight are also different. In SI units1, mass is measured in kilograms (kilograms is abbreviated kg) and weight is measured in newtons. In mathematical terms,

Weight = Mass * Gravity

  1. The value of gravity near sea level on Earch is 9.8 m/sec2. How much does a 4-kg block weigh on Earth?
    Result:
    4 kg * 9.8 m/sec2 = 39.2 newtons

  2. How much does a 5-kg block weigh on Earth?
    Result:
    5 kg * 9.8 m/sec2 = 49 newtons

  3. How much does a 3-kg block weigh on Earth?
    Result:
    3 kg * 9.8 m/sec2 = 29.4 newtons

  4. How much does a 2-kg block weigh on Earth?
    Result:
    2 kg * 9.8 m/sec2 = 19.6 newtons

  5. How much does a 1-kg block weigh on Earth?
    Result:
    1 kg * 9.8 m/sec2 = 9.8 newtons

  6. Bonus Question - answer without Interactive Physics.
    The value of gravity on the Moon is 1.67 m/sec2
    How much does a 4-kg block weigh on the Moon?
    Result:
    4 kg * 1.67 m/sec2 = 6.8 newtons

  7. Bonus Question - answer without Interactive Physics.
    How much does a 5-kg block weigh on the Moon?
    Result:
    5 kg * 1.67 m/sec2 = 8.5 newtons

  8. Bonus Question - answer without Interactive Physics.
    How much does a 3-kg block weigh on the Moon?
    Result:
    3 kg * 1.67 m/sec2 = 5.1 newtons


1In all countries other than the United States, Liberia, and Myanmar, SI units (International System of Units) are used to measure mass, weight, length, area, temperature, etc.
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