1. Weight and mass
T.H.
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2. What units are used by this weighing scale?
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3. The scale on the left uses newtons
The scale on the left uses newtons. The scale on the right uses kilograms (in red) and stones (in black). Compare the readings.
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4. Newtons are much smaller than kilograms
Newtons are much smaller than kilograms. How many newtons are there in a kilogram?
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5. It depends what planet you’re on!
On the moon, 1 kg has a weight of only 1.6 N
On earth, 1 kg has a weight of 9.8 N
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6. On Earth Sean reads 69 kg or 676 N.
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7. On the moon, Sean would still have a mass of 69 kg, but his weight would be only 110 N. So, one way to lose weight is to go to the moon.
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8. Is mass the same as weight?
What’s your opinion?
Can you think of any differences between the two quantities?
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9. Mass and weight
The weight of an object is due to the force of gravity acting on it. It is measured in newtons. A body’s weight can change depending on whether it’s on earth, the moon, mars and so on.
Mass is measured in kilograms. According to one definition, it is a measure of the resistance of a body to motion. Unlike your weight, your mass won’t change if you move to another planet.
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10. W = mg Weight = mass multiplied by the acceleration due to gravity
Jane has a mass of 58 kg. Find her weight on each of the following:
Earth
Moon
Mars
Jupiter
Sun
g / m s–2
9.8
1.6
3.71
25.95
274.13
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11. Answers
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12. A Final Question Is g = 9.8 m s–2 everywhere on earth?
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13. Answer
No. Comparing cities, it is lowest in Mexico City (9.779 m s–2) and highest in Oslo (Norway) and Helsinki (Finland) (9.819 m s–2).
Standard gravity, or standard acceleration due to free fall, usually denoted by g0 or gn, is the nominal acceleration of body in a vacuum near the surface of the earth. It is defined to be precisely  m s–2.
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