Can someone explain why the M is assigned to be anticlockwise here ?
When i assign it as clockwise , i will get -P(δ -v) , which is different from the author ...
If i do so , then , all the sign will be different
Can i do so ? Why ?
or the second example here , i can understand that M = -Pv , since M+Pv = 0 at either end when it's in equlibrium.
P/s : I know the the sign convention of the bending moment of beam is positive when the beam upwards as shown ...
For the first example , i gt M+P(∂-v) = 0 , so M = - P(∂-v) .
I am not sure whether is my concept correct or not .