Weight question?

Question

I know that W = mass x G, where G = 9.8m/s squared

So, if something has a mass of 100kg on Earth, will the calculation for its weight be 100 x (9.8 x 9.8) ?

Answer 1

no, 9.8 m/s^2 is not (9.8)^2

9.8m/s^2 is the acceleration due to the Earth.

Weight = mass * acceleration (or G)

weight = 100kg * 9.8m/s^2

weight = 980N

it doesn't always be in G. For example, the weight will be less if you are on the moon. Acceleration due to the moon is 1.6m/s^2

Weight = mass * acceleration
weight = 100kg * 1.6m/s^2
weight = 160N

you know we will weight less if we go to the moon.

Answer 2

There's no "on Earth" about it; something that has a mass of 100kg has that same mass anywhere; weight changes but mass doesn't. It's easy to get confused because much of the world uses kg for weight as well as for mass, even though they are completely different concepts.

To answer your question, no, it would just be 100 x 9.8. G isn't 9.8 times 9.8, it's 9.8 meters divided by (seconds x seconds). (That is, only the s is squared, because G is an acceleration)

Answer 3

Nope it's weight will be 100 kg * G

G = 9.8 m/s^2
1 kg = 1000 g
1 Newton = 102 gram * 9.8 m/s^2
1 Newton = 102 g*G
1 Newton = 0.102 kg * G

1 g * G = (1/102) N
1 kg * G = 1000/102 N
100 kg * G = 100 * (1000/102) N

100 * (1000/102) N = 980.4 N

The reason my answer and SOMEBODY's are not exactly the same is that SOMEBODY is just doing the arithmetic and changing the engineering units. I am using conversion values.

If you use standard conversions for kg to N (instead of g), your answer may even end up being:
980.7 N

Remember that G = 9.8 m/s^2 is the value for G at SEA LEVEL. The value changes with altitude.
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