thedarkshade Posted December 1, 2007 Share Posted December 1, 2007 Which is what you get when you set the gravitational and centripetal force terms equal, which has already been discussed. (since g = Gm/R2) ok, sorry then, I just had no time to look at all the posts! Link to comment Share on other sites More sharing options...
MrMongoose Posted December 1, 2007 Share Posted December 1, 2007 Because you're balancing the weight of the bullet with the centripetal acceleration. So the mass doesn't enter into it. Just plain not true. I'm balancing weight with centripetal FORCE as well I should. You sure Swansont? I thought the potential energy would be positive, and I seem to get the right answer. If increasing height made PE drop, wouldn't conservation make KE increase, so as you move upwards, you constantly accelerate? Link to comment Share on other sites More sharing options...
CPL.Luke Posted December 4, 2007 Share Posted December 4, 2007 yes but the mass term cancels. Link to comment Share on other sites More sharing options...
insane_alien Posted December 4, 2007 Share Posted December 4, 2007 Just plain not true. I'm balancing weight with centripetal FORCE as well I should. You sure Swansont? I thought the potential energy would be positive, and I seem to get the right answer. If increasing height made PE drop, wouldn't conservation make KE increase, so as you move upwards, you constantly accelerate? psst weight and centripetal force are the same thing. Link to comment Share on other sites More sharing options...
swansont Posted December 4, 2007 Share Posted December 4, 2007 Just plain not true. I'm balancing weight with centripetal FORCE as well I should. You sure Swansont? I thought the potential energy would be positive, and I seem to get the right answer. If increasing height made PE drop, wouldn't conservation make KE increase, so as you move upwards, you constantly accelerate? PE = -GMm/r, assuming PE = 0 infinitely far away. You have to add energy to increase r Link to comment Share on other sites More sharing options...
CPL.Luke Posted December 4, 2007 Share Posted December 4, 2007 what? maybe in this particular example they are equal, but that is not true in the general case, just feel your chair pressing into you, they are crtainly not the same thing in any instance. Link to comment Share on other sites More sharing options...
insane_alien Posted December 4, 2007 Share Posted December 4, 2007 CPL that is because there is a force counteracting the centripetal force. the centripetal force(weight) is the same but the net force is nigh on zero because of the counteracting force of the chair. Link to comment Share on other sites More sharing options...
MrMongoose Posted December 4, 2007 Share Posted December 4, 2007 That what I said, centripetal force is equal to weight, not centipetal acceleration as gareth said, so the m's cancel. If it were acceleration, we would be left with an m in the weight term. I was being very stupid with the energy admittedly :$ Link to comment Share on other sites More sharing options...
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