- #1
Mad_Eye
- 69
- 0
hi,
i've read in a lot of places that the minimum speed fora body to "finish" a vertical circle is (rg)^0.5, but I've never understood why.. they assume the if the body passes the top, it will finish the whole circle.. but i can't actually see it... can someone explain/proof it to me?
secondly, is the mentioned speed is for the bottom or for the top?
this is the proof I've seen:
(the top point)
mg + N = ma
a = v^2 / r
assume N=0
mg = mv^2 / r
v = (rg)^0.5my problem is with this formula
a = v^2 / r
the acceleration is changing, thus this is true for momentary velocity.
so v = (rg)^0.5
must be for v of the top.. not the bottom...sorry about my english :)
i've read in a lot of places that the minimum speed fora body to "finish" a vertical circle is (rg)^0.5, but I've never understood why.. they assume the if the body passes the top, it will finish the whole circle.. but i can't actually see it... can someone explain/proof it to me?
secondly, is the mentioned speed is for the bottom or for the top?
this is the proof I've seen:
(the top point)
mg + N = ma
a = v^2 / r
assume N=0
mg = mv^2 / r
v = (rg)^0.5my problem is with this formula
a = v^2 / r
the acceleration is changing, thus this is true for momentary velocity.
so v = (rg)^0.5
must be for v of the top.. not the bottom...sorry about my english :)
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