Go Back   Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Thermodynamics and Fluid Mechanics Thermodynamics and Fluid Mechanics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Jul 15th 2019, 04:53 AM   #1
Junior Member
 
Join Date: Jul 2019
Posts: 2
terminal speed of the vessel

In vacuum and weightlessness, at the bottom of a cylindrical vessel (a cup), there is a layer of solid substance of molar mass μ. This substance sublimes slowly (evaporates from the solid phase into gaseous phase) and pushes thereby the vessel to the opposite direction. Estimate the terminal speed of the vessel. The mass of the vessel M, and the initial mass of the substance m ≪ M; the temperature of the vessel is T; the process can be assumed to be isothermal (cooling due to evaporation and heat radiation remains negligible). The
cross-sectional area of the vessel is A.
howard24 is offline   Reply With Quote
Old Jul 15th 2019, 05:05 AM   #2
Senior Member
 
Join Date: Aug 2010
Posts: 434
If this is "in vacuum and weightlessness" what do you mean by "up"? And why would a gas push the vessel "up"?
HallsofIvy is offline   Reply With Quote
Old Jul 15th 2019, 05:11 AM   #3
Junior Member
 
Join Date: Jul 2019
Posts: 2
me neither understand that. but the answer should be:
V=m/M*sqrt(RT/miu) and I do not know how to get to it
howard24 is offline   Reply With Quote
Old Jul 15th 2019, 07:17 AM   #4
Senior Member
 
Join Date: Apr 2017
Posts: 513
Originally Posted by HallsofIvy View Post
If this is "in vacuum and weightlessness" what do you mean by "up"? And why would a gas push the vessel "up"?
No where does the word "up " appear ..

The solid is in the base of the cup , subliming , that's to say atoms separate from the solid surface , become gas , the gas can only exit in one direction , the mouth of the cup ,the reaction pushes the cup the other direction.

The terminal speed must be dependent on the speed(temperature) of the gas molecules ... it must be the same as the velocity of gas molecules , because then the molecules cannot impact the surface imparting momentum , the surface is moving away as fast as they are travelling .

Last edited by oz93666; Jul 15th 2019 at 07:28 AM.
oz93666 is online now   Reply With Quote
Old Jul 15th 2019, 09:25 AM   #5
Senior Member
 
Woody's Avatar
 
Join Date: Jun 2016
Location: England
Posts: 1,069
Look at the momentum transfer
the momentum of the cup must be equal but opposite to the momentum of the gas molecules.

Also look at the ideal gas law.
__________________
~\o/~
Woody is offline   Reply With Quote
Old Jul 15th 2019, 09:46 PM   #6
Senior Member
 
Join Date: Apr 2017
Posts: 513
Originally Posted by Woody View Post
Look at the momentum transfer
the momentum of the cup must be equal but opposite to the momentum of the gas molecules.

Also look at the ideal gas law.
Unnecessary ...

All you need is the velocity of the gas molecules ...
that will be the terminal speed of the container
Because momentum will continue to be imparted to the container, increasing it's speed .. until it is moving away so fast gas molecules can no longer hit the surface sublimating.
oz93666 is online now   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Thermodynamics and Fluid Mechanics

Tags
speed, terminal, vessel



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Vessel leak detecting with measuring Gas properties mehdiaq Thermodynamics and Fluid Mechanics 0 Jul 17th 2014 11:42 AM
why we commonly use only two saddles in horizontal pessure vessel dhaya Kinematics and Dynamics 1 Sep 10th 2012 06:07 AM
Calculation of pressure inside cylindrical vessel harshvardhan Advanced Thermodynamics 0 Aug 30th 2010 09:53 AM
terminal velocity bobey Kinematics and Dynamics 2 Apr 21st 2010 10:40 PM
Temporarily communicating vessel isolated hydroelectric power plant epozah Thermodynamics and Fluid Mechanics 15 May 25th 2009 08:31 AM


Facebook Twitter Google+ RSS Feed