Physics -- Gravitational Field

用戶36244

2008-01-28 4:01 am

The symbol, g, stands for two meaning.
1) Acceleration due to gravity ( Unit: m/s^2)
2) Gravitational field strength ( Unit: N/kg)
Although their symbols are also g, they have different units. So, how can they be the same? Is there no any difference among the two?

回答 (1)

Audrey Hepburn

2008-01-28 5:24 am

✔ 最佳答案

The words ‘acceleration due to gravity’ is not a good word. From now on, you should use gravitational field strength.

For the acceleration due to gravity, a = g, it is just a coincidence.

By g = -GM/r2, F = -GMm/r2, we get the relationship F = mg. In this case the unit of g is Nkg-1

By Newton’s 2nd law of motion, F = ma, in this case, the unit of a is ms-2.

Therefore, we get a = g. This means that the magnitude of acceleration of the object undergoing freefall is g.

However, they are representing two different physical quantities.

Proof of dimensions:

Nkg-1 = (kgms-2)kg-1 = ms-2

參考: Myself~~~

👍 0 👎 0