Question

An object weigh 240N on Earth surface of the earth. At what height above the earth's surface it weight 15N ???

Answer 1

The following formula approximates the Earth's gravity variation with altitude:
g` = g(r/(r+h))^2 Where:
g` is gravity at some altitude.
g is gravity near earth’s surface.
r is earth’s mean radius.
h is the altitude.

Now for you to feel half of your weight, g` should be half of g.
This means h should be ~2639 KM (Assuming earth’s mean radius = 6371 KM).

So if you reach at a height of about 2700 KM above the sea level, you body will weigh around 30 N.

Answer 2

Answer:

It is given that the weight of the object on the earth is 120N. That is W(e)=120N. Acceleration due to gravity is 10m/s.

Mass of the object on earth, m(e) is calculated as follows.

We know, W(e)=M(e)×g

Therefore, 120N=M(e)×10. That is, M(e)=120/10=12kg

Thus, the massof the object on earth is 12kg. We know that the mass of the object remains the same through out the universe. Hence, mass of the object on the moon is also 12kg.

We know, weight of the object on the moon =1/6 of the weight of the object on the earth.

Therefore, W(m)=1/6×W(e)

That is, W(m)=1/6×120N=20N

Hence, the weight and mass of the object on the moon are 20N and 12kg respectively.