Passengers in an aircraft are subject to the Normal and Gravity Force acting on them at a low 'orbit', so tiny that it can be many times compared to the same surface of the earth when speaking in general terms.
In a high orbit space vehicle or in the same space, said force decreases considerably or simply disappears, generating the sensation of weightlessness.
Remember that the Force of Gravity is given under the principle

Where,
G = Gravitational Universal constant
M = Mass of the planet
m = mass of the object
r = Distance from center of the planet
When the radius grows considerably the gravitational force begins to decrease.
The inaccurate measurements must be similar to the other two measurements (ex; 590, 589, 599), but different from the actual volume of water. (Ex; the actual volume is let say.. 100, but you measured 50, 49, 40)
This answer is true the earth always stays at one speed
Answer:
m = 0.4 [kg]
Explanation:
Weight is considered as a force and this is equal to the product of mass by gravitational acceleration.

where:
W = weight = 0.8 [N]
m = mass [kg]
g = gravity acceleration 2[N/kg]
Therefore:
![m=W/g\\m = .8/2\\m = 0.4 [kg]](https://tex.z-dn.net/?f=m%3DW%2Fg%5C%5Cm%20%3D%20.8%2F2%5C%5Cm%20%3D%200.4%20%5Bkg%5D)