naplesZ Posted July 7, 2005 Share Posted July 7, 2005 Does anyone know how to figure out how much force something will have when it impacts with something else? If so can you show me the formula or tell me were you got it from. Let say something moving at 658 mph. What if any other info would you need to find out the force in pound per sqaue inch. Thanks Quote Link to comment Share on other sites More sharing options...
Guest Phil1934 Posted July 7, 2005 Share Posted July 7, 2005 You will need to have a deformation. Otherwise the force is infinite. For your example convert MPH to FPS. 1 G is 32.2? FPS. Suppose the deformation is over one second. Figure G. Multiply by weight. Also can be done with deformation in inches or feet. Then you would figure what free fall equates to MPH and what is length of deformation and take ratio times weight. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 7, 2005 Share Posted July 7, 2005 1/2Mass X velocity squared? Quote Link to comment Share on other sites More sharing options...
GabeRoc Posted July 7, 2005 Share Posted July 7, 2005 might i ask what this question is in relation to? depending on what information you are looking for you may actually be looking for energy transfered (as terry suggested) rather than force at impact. if you want to find the force at impact, convert your velocity to FPS (in your case 658*5280/360) find the energy of the item (.5*m*v^2) then divide that by the distance the item travels while transfering the energy. be sure to use feet for distance, slugs for mass. this also assumes that the item doing the striking is much smaller than the item being struck. if you'll let us know a little more about what specific case you are dealing with i'd say that an answer with less vaugeness could be had. --gabe Quote Link to comment Share on other sites More sharing options...
blueovalz Posted July 7, 2005 Share Posted July 7, 2005 (in your case 658*5280/360) Is that 3600 instead of 360? Quote Link to comment Share on other sites More sharing options...
naplesZ Posted July 7, 2005 Author Share Posted July 7, 2005 Wow thanks for the replies I was searching on the internet when it hit me that I should try here. A lot of you guys blow me away with some of the stuff that you do involving your cars so I figured I give it a shot. I basically had an Idea for an invention a while back and was just trying to find some basic Info. The item that would be moving would way around 4-5 lbs.. I doing more research to get an exact #. The distance traveled would be under a thousand feet and would change. Sorry If I'm being a little cryptic but I don't want to spill the beans to everyone just yet. It's probably already been done or won't work but you never know.I geuss I need to know force of impact. So I can look into the materials that would be required. Pm me If you need any more Info. Thanks again everyone Quote Link to comment Share on other sites More sharing options...
GabeRoc Posted July 7, 2005 Share Posted July 7, 2005 Blueovalz, yeah. 60*60=3600 not 360. nice catch. naplesZ, the question is not how far the thing moves, but how far it goes from the time it touches the thing it hits and it stops. for instance: if you were to shoot a gun into a block of wood, the distance measured would be how far the bullet went into the wood. from that information you could get the average force applied by the bullet to the block of wood. this is not to say that you would get the largest force, nor that the average would be what you needed to design for, but it is at least a number to start with. there are other considerations as well, but maybe this will get you started. --gabe Quote Link to comment Share on other sites More sharing options...
baddriver Posted July 7, 2005 Share Posted July 7, 2005 Are you concerned with the actual force of impact, or the velocity of the object after it is struck? If you want the final velocity, conservation of momentum is probably a better way to estimate the outcome. If you want to know the destructive force, use kinetic energy. And if you want to know the impact, use momentum divided by the time elapsed during deformation. You have to have some idea of the hardness of the two objects. Quote Link to comment Share on other sites More sharing options...
Moridin Posted July 7, 2005 Share Posted July 7, 2005 Wow thanks for the replies I was searching on the internet when it hit me that I should try here. A lot of you guys blow me away with some of the stuff that you do involving your cars so I figured I give it a shot. I basically had an Idea for an invention a while back and was just trying to find some basic Info. The item that would be moving would way around 4-5 lbs.. I doing more research to get an exact #. The distance traveled would be under a thousand feet and would change. Sorry If I'm being a little cryptic but I don't want to spill the beans to everyone just yet. It's probably already been done or won't work but you never know.I geuss I need to know force of impact. So I can look into the materials that would be required.Pm me If you need any more Info. Thanks again everyone I don't think they're talking about the total distance traveled, but the distance traveled during impact. Like a car crashing into a wall. Upon impact it the back end travels X number of feet? I think that's right. Anywho, I really start getting into good college physics next semester and will know much more then. Quote Link to comment Share on other sites More sharing options...
Guest zfan Posted July 7, 2005 Share Posted July 7, 2005 My math sucks! Mike Quote Link to comment Share on other sites More sharing options...
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