Lunar Weight?

Question

Suppose that I weigh 180 pounds on the Earth's surface at mean sea level.

I and 3 other objects are going to the moon.

1. A ridgid "baloon" filled with hydrogen.
2. Bathroom scales
3. Doctor's scales - those kind that have weights to counter balance.

I weigh the same on both scales (with my space suit on, of course - discount the effects from the suit).

When I hold onto the hydrogen baloon, I weigh 120 ponds on both scales.

Now, what weights would I expect on the moon if I repeated the experiments there?

ps - assume the moon's gravity is 1/6 (0.17) that of the earth.

joe

Answer 1

Without the balloon, the doctor's scale would still read 180 pounds (technically that type of scale reads mass, not weight).

Without the balloon, the bathroom scale would read 30 pounds - one-sixth of your weight on Earth.

Since there is no atmosphere on the Moon, the balloon would weight you down some. I think you can figure out how much, using what's-his-name's law about buoyancy. I'll get back to you on that....

Thinking about it more, I'm not sure it can be done - I think you need to know the material the balloon is made out of. If the mass of the balloon material is negligable, then you need to know the ratio of the density of hydrogen to the density of air on Earth, multiply that ratio by 60 pounds to find the mass of the hydrogen inside the balloon.

Answer 2

You would weigh 30 lbs plus 1/6 the earth mass of the baloon.

The moon has no atmosphere so the baloon would not decrease your weight.

Answer 3

They don't need weights in their boots, as 1/6th gravity is more than enough to keep them down. The spacesuit and backpack is quite heavy too. The backpack is properly known as the portable life support system (abbreviated to PLSS< pronounced 'pliss') and is an integral part of the spacesuit. The suit itself consists of several layers. There is an undergarment, through which a network of plastic tubes runs close to the astronaut's skin. These tubes have water pumped through them for cooling, and this water is one of the things contained in the PLSS. Then there is the pressure garment, which is basically rubber and is filled with oxygen, also carried in the PLSS. The helmet and gloves complete the suit. For lunar exploration they also wore a thick pair of boots to protect the feet of the suit from the abrasive moon dust. So, the PLSS mostly contained water and oxygen, but also important was the communications equipment that allowed the astronauts to talk to each other and mission control, and this was also in the PLSS. The PLSS was not brough back to Earth, although contrary to an earlier answer the PLSS was not left at the foot of the ladder before they went inside the LM, as there was no way to disconnect the PLSS and retain suit pressure. The astronauts entered the LM, repressurised the cabin, then disconnected the PLSS and connected their suits directly to the LM oxygen supply before depressurising again and throwing the PLSS, boots and other unwanted items out the door onto the surface. They then repressurised the cabin and removed their spacesuits.

Answer 4

Since da moon has no atmosphere (or air), then the baloon would actually slightly weight you down. But other than that, it will roughly be the same percentage decrease.