- #1
greg_rack
Gold Member
- 363
- 79
- Homework Statement
- Determine the ratio ##\frac{a}{b}## for which the shear force will be zero at the midpoint C of the beam
- Relevant Equations
- Torque
Hi guys, I'm wasting much time on this problem but still can't manage to get to a solution; I'll attach my attempt below.
![to delete.png to delete.png](https://www.physicsforums.com/data/attachments/272/272877-65ef4fa3efc811fea44ac0ea2e317926.jpg)
I started with drawing the FBD of the beam "sectioned" at point C, in order to find an expression for the internal shear force at that point and then equal that to zero.
First I calculated the reaction force Ay as a function of a and b, then assumed Vc=0 in the equation for vertical equilibrium of internal forces in point C and solved the equation for ##\frac{a}{b}## but which of course takes me to a wrong number, since I got a negative ratio of distances!
![to delete.png to delete.png](https://www.physicsforums.com/data/attachments/272/272877-65ef4fa3efc811fea44ac0ea2e317926.jpg)
I started with drawing the FBD of the beam "sectioned" at point C, in order to find an expression for the internal shear force at that point and then equal that to zero.
First I calculated the reaction force Ay as a function of a and b, then assumed Vc=0 in the equation for vertical equilibrium of internal forces in point C and solved the equation for ##\frac{a}{b}## but which of course takes me to a wrong number, since I got a negative ratio of distances!