- #1
diadiaria
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1. There is a beam with labels point A on the left hand side of the beam and point B on the right hand side of the beam. The beam is supported by bolts on side B (that can handle up to 4000 lb). There is no support on side A, so a support has to placed at some distance from B to support the beam. The beam weighs 2000 lb and is 100 feet long.
Sum Fx=0
Sum Fy= Fsupport + ForceB - Fbeam=0
Sum of Moments (taken through point B)
Sum of CCW Moments=0=Sum of CW Moments
(Fbeam)(distance from acting weight of beam to B)= (Fsupport)(Distance from support to B)
First, I solve the sum Fy equation so I can solve for Fsupport.
Sum Fy= Fsupport + ForceB - Fbeam=0
Sum Fy= Fsupport + 4000- 2000=0
But this gives me Fsupport = -2000 lb. Theoretically, there could be a negative force, but this support is supposed to be underneath the beam, giving an upward and positive force.
Anyway, I didn't think this was right, but the next step would obviously be to solve for distance from support to B. I assume the distance from the force of the beam to B is half the length of the beam
0= (Fbeam)(distance from acting weight of beam to B)= (Fsupport)(Distance from support to B)
0= (2000 lb)(50')= (-2000 lb)(distance from support to b)
I guess to sum up the questions:1) If the bolt force is greater than the weight of the roll, how am I supposed to prove this scenario will hold when the forces equation says I need an extra downward force from the support?
Thanks!
Homework Equations
Sum Fx=0
Sum Fy= Fsupport + ForceB - Fbeam=0
Sum of Moments (taken through point B)
Sum of CCW Moments=0=Sum of CW Moments
(Fbeam)(distance from acting weight of beam to B)= (Fsupport)(Distance from support to B)
The Attempt at a Solution
First, I solve the sum Fy equation so I can solve for Fsupport.
Sum Fy= Fsupport + ForceB - Fbeam=0
Sum Fy= Fsupport + 4000- 2000=0
But this gives me Fsupport = -2000 lb. Theoretically, there could be a negative force, but this support is supposed to be underneath the beam, giving an upward and positive force.
Anyway, I didn't think this was right, but the next step would obviously be to solve for distance from support to B. I assume the distance from the force of the beam to B is half the length of the beam
0= (Fbeam)(distance from acting weight of beam to B)= (Fsupport)(Distance from support to B)
0= (2000 lb)(50')= (-2000 lb)(distance from support to b)
I guess to sum up the questions:1) If the bolt force is greater than the weight of the roll, how am I supposed to prove this scenario will hold when the forces equation says I need an extra downward force from the support?
Thanks!