I'm really confused on this problem. I drew a FBD and got determined my forces in the x to be N(from plank right on plank left)=frictional force from the floor, and in the y i got the N(from floor onto the planks)=mg. I'm having trouble with the sum of the torque forces and in general figuring out the problem. Any help is greatly appreciated!!!
Two identical uniform beams, each having a mass of 3 kg, are symmetrically set up against each other on a floor with which they have a coefficient of static friction µ = 0.603.
a) What is the minimum angle the beams can make with the floor without falling?
Θ = ? (°)
b) For the angle calculated in part (a), what is the magnitude of the force exerted on one beam by the other beam, at the apex?
|F1 2| = ? (N)
Next a heavy point mass 3 kg is balanced on the apex.
c) What is the normal force exerted on each beam by the floor?
|N| = ? (N)
d) For this case, what is the minimum angle the beams can make with the floor without sliding?
Θ = ? (°)
Two Identical Beams leaning against each other in static equilibrium?
RFx
It is also the frictional force at the floor
summing torque about the floor
m*g*cosθ*L/2=RFX*sinθ*L
RFx=mg/(2*tanθ)
RFx=m*g*µ
tanθ=1/(2*µ)
a) θ=39.7
b)
RFx=m*g/(2*tanθ)
17.7 N
c) The normal force is the sum of the vertical forces 3*g from the beam and 1.5*g from the point mass
Normal force=4.5*9.81
44.1 N
d)
sum torque about the floor again
3*g*cosθ*(L/2+L/2)=RFX*sinθ*L
solve for RFx
RFx=3*g/tanθ
35.5 N
RFx=3*g/tanθ
RFx=4.5*g*µ
combine
4.5*g*µ=3*g/tanθ
solve for θ
tanθ=3/(4.5*µ)
47.87 degrees
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