Questions and discussion for this lecture live here. Fire away by hitting Reply below 
Hello Sean,
In video 19:00 - 19:11 range or as can be seen in screenshot, i just wanted to clarify bulletpoints as mentioned below whether i understood correctly or not ;
1- SFD and BMD are drawn based on deformation sign convention. Therefore, we will draw our graphs based on this sign convention’s lead i.e if we have clockwise moment of 50 KN.m at point x=5, that means we shall draw in BMD as -50 KN.m
2- Normally in previous examples, we used deformation sign convention signs for moment and shear, but for this example between 19:00 - 19:11, we state Mcut as clockwise moment (logically to balance the left moment), and because the value come up positive with this assumption which is the inverse of deformation sign convention we stated as - value in BMD.
Can we simplify the sign convention as below :
1- if we have a cut, use deformation sign convention to state internal moment and shear forces and we are drawing SFD and BMD totally for internal forces or in other words the reaction of the system purely, but we have to use static sign convention for the cuts equlibrium to ensure system is static.
Therefore, clockwise moments and upwards shear are positive. Considering these, if we got a negative value from static sign convention equation for Minternal and Vinternal that shall mean that we shall have negative values for Minternal and Vinternal in SFD and BMD. However, if we have a positive values for them, that means our deformation sign convention sign assumptions were correct, and we can directly treat them as postiive values in SFD and BMD.
Sorry for huge explanation and question Sean, i do not know how else to explain it. It is very crucial point for understanding and i want to make it right.
Thanks a lot in advance,
Thanks for your time.
Burak
