Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

Everything posted by Primarygun

  1. thank you every body first. If the radial acceleration is very large, does it affect the magnitude of the velocity of the object ? Actually, I had a similar question in a textbook. Given the distance between the moon and the earth, the masses of them respectively, find the gravitational potential energy PE if the moon orbits the earth truly in a circular motion. Then, find the kinetic energy of the moon. so, do you expect PE > KE od KE > PE? The answer said: PE > KE for magnitude since it is in a bound system. I wonder if this is true every time. That's a little bit different from the answer Is an external force resulting the difference?
  2. Is it possible for an object to achieve the required escape velocity around a planet but not leaving the planet? I still have some problems concerning the radial acceleration .
  3. If there's a vacuum at the destinated space as you described, what is the pressure of water in contact?
  4. Yes, it is the case. Why is it 1 atm +..? The weight of water trapped in the tube is not large enough to generate 1 atm , isn't it?
  5. I could fully understand this statement. But, if a change in direction is resulted in a change ( tiny change) in one of the components of velocity, right?
  6. IF I invert a test tube, with it fully filled in with water, and put it above a beaker of water, just like the process of electrolysis. What is the pressure at the bottom and at the mouth of the test tube? I guess the pressure at the mouth is 1 atm, but where supports this relatively large value apart from the little weight of the water held?
  7. What does this mean? You didn't use the diluted solution?
  8. means that the H2SO4 has 98% of the total weight of a sample of H2SO4 solution. In order to find out the molarity of the sulphuric acid, there's a pretty good method. Find out how many moles of H2SO4 are there in 1 dm^3 of water. Then it is equal to the molarity of the acid. Molarity= no. of mole of a substance / volume of solution. Since there's no departure of any H2SO4 molecules, it follows that there exists the amount of H2SO4 molecules. In this case , the molarity decreases as a result of the decrease in Volume of the solution
  9. I don't know, but there's an increase in velocity in the perpendicular way, thar is v=a *(delta t) I suggest that as delta t is near zero, the increase of that component us also near zero.
  10. Consider there is a car driving in a horizontal circular path, as stated in my book, a radial force exists and causes the car to accelerate towards the centre. Here the questions are: why the acceleration must be towards the centre? with a positive acceleration in a direction perpendicular to the motion of the car, the car should be accelerate towards the centre and this results in an increase in the speed of the car but the fact indicates that is impossible, why? Besides, what is centrigual force? Is it prerequisite in order to have a complete understanding of rotation? This question I've tried the web links in my books, and other E-books, however, I still get a unclear mind/
  11. I suggest Avast though I haven' tried the other one. It offers a very frequent update of virus details. Also, you can have one year trial of it with all the functions /
  12. Thanks everyone. I found that once I press the Start Debugging, there's an exe coming out somewhere in the C driver.
  13. How do you export as an exe in visual basic? thx
  14. What's the difference between Visual basic and visual studio? how can I export an exe from a form in visual studio?
  15. Recently, I reinstalled my Window as it's almost a year after the purchase. To my knowledge, the speed of the computer is inversely proportional to the complexity of the regedit. I'd like to get a spare copy of my present regedit . Here came a problem. I saved my present regedit and I loaded it again. It started loading but finally, a small window with a statement telling that it can't be loaded as one or more programs are using the regedit/ I have a lot of softwares running in my system .which program should be terminated by a second
  16. Doesn't Window XP Home Edition have IIS?
  17. OK thanks guys. I consider using Linux.
  18. ABout using the TypSoft What things do I need to set? I set the "root", port but I see nothing in my ftp://(my ip address).
  19. Does anyone know how to extend the trial period by cheating in the regedit? Rarely does anyone talk about linux in my place. I don't know why.
  20. I am trying to make my own FTP server. So far, I tried using the "Serv-U" and I found it useful. However, it offers a period of 30 days for trial only. Does anyone know other good softwares accomplishing the task?
  21. As I mentioned in another thread. It is hydrated iron(III) oxide for the rust. You can make iron oxide very easily, burning it in air, but you only get a handful of black solid only, but not the reddish brown rust. As I may be in a dearth of the knowledge here, I'd only mention several factors that help speed up the rusting, I hope that they are useful. 1.Temperature 2.Presence of acidic substance, elctrolyte 3.Attachment to a less reactive metal 4.Scratched surface, resulting in a high density of charge/ Edit: and its just tables salt and tap water right? Sorry, I don't understand. May you put down the question briefly?
  22. Necc stands for no ecc?
  23. rust is hydrated iron(III) oxide. iron(III) oxide ---> hydrated one is slow
  24. I can't believe that diamond can transfer heat much faster than others, though I know it is a good heat conductor. and at temperature, gold is a little bit better than aluminium
  25. A tiny difference from my answer. In my region, we would put down the precipitate instead of just the ion.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.