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ledphones
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Homework Statement
The above figure shows a uniform iron beam of mass 253 kg and length L = 3 m. The cable holding the beam in place can take a tension of 1300 N before it breaks. Use the Young's Modulus for steel to be 200e9 N/m2. (You may ignore the small mass of the cable in this calculation.) a)What minimum length of the cable?
Lengthmin= m
HELP: How will the torque placed on the beam by the cable depend on the angle between the cable and the beam??
b)Assume the cable is made of steel and has a diameter of 1". How much will it stretch before it breaks?
Δmax = cm
HELP: Young's modulus for steel is 200X109N/m2.
Homework Equations
The Attempt at a Solution
for a)
I set the forces in the x up like :
mgcos(phi)-Fcos(theta)=0
y:
Fsin(phi)+Tsin(theta)-W=0
torque
-Wdsin(180)+TLsin(theta)=0
where phi is the angle of the wall the normal force and theta is the angle of the cable and the beam. i don't know where x comes into play
for part b i think it would be like this
stress=1050/(1.27^2pi)
stress/20000000=strain
change in L will be strain*the L from part a