octopus001
發表於 9-9-2008 22:25:29
冇力 仲有a ga咩 - -?[]
j32738
發表於 10-9-2008 18:54:34
乜W唔係=mg咩= =
x-Stephen-x
發表於 10-9-2008 19:47:33
A bob of mass m is suspended from a fixed support by light string. A force F is applied to the bob so that the string makes angle with the vertical. What is the minimum value of F required to keep the bob in static equilibrium?
draw a diagram..
mg向下...T向N@E.....你差一個F....而F係向邊個方向都得ge....而最短ge F 係 perpendicular to T...
so sin@=F/mg
F=mgsin@
Zend
發表於 10-9-2008 20:56:22
原帖由 octopus001 於 9-9-2008 10:25 PM 發表 http://www1.nakuz.com/bbs/images/common/back.gif
冇力 仲有a ga咩 - -?[]
I mean
假設無applied force, 個direction of acceleration係邊