What is his weight in deep space, far away from any celestial body? What is his mass there?
2007-08-28 07:11:46 · 12 answers · asked by Pascal 4 in Science & Mathematics ➔ Physics
His weight is NOT 0 but will approach zero as long as there is another mass present in space according to the formula:
Fg = GMm / r^2
If the radius was increased, then Fg will decrease BUT will never hit 0.
And as long as Fg does not = 0, then there will always be a weight (force)...his mass however will always be the same.
2007-08-28 07:17:01 · answer #1 · answered by Anonymous · 1⤊ 1⤋
Under non-relativistic conditions, mass m is fixed. So your astronaut will be m = 70 kg no matter where in the universe she goes.
Weight, on the other hand, is just a special name we give to the force due to gravity. As a force F = GmM/R^2; where m is the astronaut (who is watching her weight), M is the mass of the biggest celestial body in the 'hood, G is a constant of proportionality, and R is the distance between the centers of m and M.
On Earth's surface, her weight is We = mg; where g ~ 10 m/sec^2 Now your astronaut moves way out into space so that Rs >>> Re from Earth's mass. In which case, Ws = GmMe/Rs^2 is her weight in deep space.
To see what effect moving out into space might have, we take the proportion Ws/We = GmMe/Rs^2/GmMe/Re^2; so that Ws = We (Re/Rs)^2 = mg (Re/Rs)^2. If we set Re = 1 Earth radius; then Ws = We (1/Rs)^2 and we can see, for example, that your fearless astronaut will weigh 1/4 what she weighed on Earth if she goes into space the equivalent of just double Earth's radius (i.e., Rs = 2 Re).
As you can see, as your astronaut gets farther and farther away from the dominant mass (e.g., Me), her weight decreases inversely proportional to the square of the distance (1/Rs^2) from the big mass.
Now, to a point, there are a lot of big masses out there in space. There are billions of galaxies each with billions of suns, many of which are far more massive than our average Sun. So my point is this, as the astronaut is pulling away from one massive mass, she's probably nearing another mass. In which case, she will always have some weight; it will not be zero in all likelihood.
2007-08-28 08:09:28 · answer #2 · answered by oldprof 7 · 0⤊ 0⤋
Weight is a function of gravatitional pull. In other words a person will weight more on a planet with higher gravity than earth. Deep space has no gravitational pull. Therefore the person weighs nothing. Zero.
Mass is a function of physical substance or matter. His mass will not change. It will be 70 kg.
2007-08-28 07:20:07 · answer #3 · answered by timdoas 3 · 1⤊ 1⤋
As everyone said, his mass would continue to be 70kg.
Sidney is correct in that the weight would not truly be zero but the question's intent seems to be that "deep space" implies negligible (read "zero") gravitational force acting on him. In a practical sense, his weight would be zero. In a precise sense, it would be negligible.
Also, Sidney mentions that his weight would definitely be zero. This is not necessarily the case. IF (and that's a big "if") the matter around him in all corners of the universe were distributed in such a way that the net gravitational field were zero at his location (and he was a point mass), he would still have - in a precise sense - zero weight. :D
2007-08-28 07:44:16 · answer #4 · answered by Anonymous · 1⤊ 0⤋
Weight and mass are relative.Mass change is relative to the Power that give motion to the mass.
Weight is relative between two masses interacting in a gravity field.
The Astronaut mass depends how fast he is moving; the faster he moves the more mass loss he experiences.
If the astronaust mass is not interacting with an external mass and is not moving ,his mass should not change.
The only interaction his mass has is with the substance of space whose pressure is keeping the astronaut from disintegrating.
2007-08-28 07:45:09 · answer #5 · answered by goring 6 · 0⤊ 1⤋
Weight is zero, mass is 70 kg.
2007-09-01 06:12:34 · answer #6 · answered by johnandeileen2000 7 · 0⤊ 0⤋
His weight is zero, and his mass is 70 kg.
This is because weight depends on the gravitational attraction between two and since there is no such attraction in space, weight cannot exist.
This is proved by the formula, F=ma.
Force = mass x acceleration.
2007-08-28 07:30:58 · answer #7 · answered by Roger 3 · 1⤊ 1⤋
weight = 0 lbs
mass = 70 kg
2007-08-28 07:14:35 · answer #8 · answered by Anonymous · 0⤊ 1⤋
The weight of the astronaut will be ZERO... That is why he floats in the space.... get it? no gravity to pull him then no weight but is there but when g=0 then weight mg = 0....
2007-08-28 07:19:58 · answer #9 · answered by ARC--loves science 2 · 0⤊ 1⤋
Mass doesn't change, it is universal. The force exerted
on the mass is what changes. His mass remains 70kg,
and the force exerted on him is probably negligable
due to distance.
2007-08-28 08:08:15 · answer #10 · answered by active open programming 6 · 0⤊ 0⤋