However there is a point load at joint E. Are you sure that rule 2 still apply to that? As far as I know you can't count member/s as zero force if there is a reaction or external load at the joint it is connected with.
+aaronwan96 the reason for that not being a zero force member is because you have 4 members attached to that spot. For the colinear rule to work you have to have 3 members there....or one of the shootoff members would need to be a zero force to make it three members in that spot. You can also use the method of joints to solve after you have knocked off some of the zero force members you absolutely know. Hope that helps.
how can you analyze joint C and say that CF is not a ZFM, if we were to look it before we look at FE, there is no more CD, implying only 3 joints connected. We only look at the joint for analysis. Also, GF would have a force going into the joint F... so wouldnt FE have a force going left? leaving your reasoning incorrect?
which zero force member rule applies to EF? Please explain why? thanks for the tutorial!
+Vincent Subramaniam Rule 2 is what is applied there. Because DE is zero then you've got rule 2 applying. Hope that helps.
However there is a point load at joint E. Are you sure that rule 2 still apply to that? As far as I know you can't count member/s as zero force if there is a reaction or external load at the joint it is connected with.
Civil Engineering Academy thankyou sir
Migs Dali it is still a ZFM because although there is a load at Point E, it is exclusively horizontal while EF is exclusively vertical.
Isn't BC a zero force member as well since it is collinear to CD member ?
+aaronwan96 the reason for that not being a zero force member is because you have 4 members attached to that spot. For the colinear rule to work you have to have 3 members there....or one of the shootoff members would need to be a zero force to make it three members in that spot. You can also use the method of joints to solve after you have knocked off some of the zero force members you absolutely know. Hope that helps.
how can you analyze joint C and say that CF is not a ZFM, if we were to look it before we look at FE, there is no more CD, implying only 3 joints connected. We only look at the joint for analysis. Also, GF would have a force going into the joint F... so wouldnt FE have a force going left? leaving your reasoning incorrect?