[AL] phy static

octopus001

冇力 仲有a ga咩 - -?[[yoyo_119]]

j32738

乜W唔係=mg咩= =

x-Stephen-x

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

原帖由 octopus001 於 9-9-2008 10:25 PM 發表
冇力 仲有a ga咩 - -?[[yoyo_119]]

I mean
假設無applied force, 個direction of acceleration係邊