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# Physics/RATE OF ASCENT

Question
QUESTION: If I had two weights one that was 100 pound and an other that was 10 pound both weights are attacked to a balloon filled with hydrogen, or helium or ammonia gas it doesn't matter. the lifting gas in both balloons is just enough to lift both weights slightly off the ground. My question is if I add one pound of free lift extra to each balloon will they raise at the same rate. If yes or no please explain. I'm try to understand the factors that go into ascent rate. THIS IS NO A HOMEWORK QUESTION

ANSWER: I think you mean "not" a homework question.  And it does read like a homework question, but it's so simple that you should be able to elaborate for yourself when I ask you the following:
Which one has more mass, and does more mass mean less acceleration when you have your 3 lb net lifting force up or not?  Both have the same total net force, 3 lbs.  One has more mass.  Newton's most basic equation...

---------- FOLLOW-UP ----------

QUESTION: Thank you so much, so they do ascend at different rate go that. But do they reach the same height? I'm thinking yes, because the same free lift in both balloon will reach a neutral buoyancy, to cancel out the free lift at a different height. Can you please telling if my thinking is correct. And one last thing what is the formula to figuring out what the Ascent rate might be?
If you have it. Again this is not a homework question. I want to send a payload 10 miles up and have it ascend at a certain rate. Any information that you can give me would help. Thanks in advance. Trying to find out the answers to my question online is hard the internet suck you ask one question you get millions of pages with half an explaination or something to advance or not advance enough.

You can't calculate that rate.  It depends on drag forces, how much the balloon expands as it rises and the pressure drops, many factors.  They won't reach the same height, their balloons are totally different.  It's hard to tell without knowing specifics of the design anything about how high this balloon will go.

Physics

Volunteer

#### Dr. Stephen O. Nelson

##### Expertise

I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.

##### Experience

I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Education/Credentials
Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.