# Beam on supports with a joint

1. Mar 16, 2015

### Karol

1. The problem statement, all variables and given/known data
Pay attention that the left support A is a fixed axis and the right, B, is a free moving axis. C is a joint.
The left beam (to the joint): 2m, 6[kN], the right beam: 3m, 10[kN]. What is the force F.

2. Relevant equations
Moments: $M=F\cdot L$

3. The attempt at a solution
To support he right beam 5[kN] must be applied upwards on the joint. moments around A:
$$1.4\cdot F=6\cdot 1+5\cdot 2$$
$$1.4\cdot F=16\rightarrow F=11.43$$
It should be F=10

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2. Mar 16, 2015

### paisiello2

I assume C is a pinned joint?

It seems to me that there is a mechanism where joint C would need to move up in order to develop a sufficient load from the right side beam for equilibrium.

You may want clarify things and draw a free body diagram with all the reaction forces and beam lengths labeled.

3. Mar 16, 2015

### Staff: Mentor

I think you'll find that if you change that 1.4m to 1.6m your answers will all be in agreement with the book.

4. Mar 16, 2015

Thanks