1. The problem statement, all variables and given/known data
A circular specimen of glass is loaded using the three-point bending method. Compute the minimum possible radius of the specimen without fracture, given that the applied load is 4000 N the flexural strength is 65 MPa, and the separation between load points is 35mm.
2. Relevant equations
Flexural Strength = (FL)/(pi*R3) where F is the load at fracture, L is the distance between support points (in mm), and R is the radius of the specimen.
3. The attempt at a solution
Flexural Strength = (FL)/(pi*R3)
so
R = cube root of ((4000N)(0.035m)/(pi*6.5*10^7))
R = 8.818 mm
This is not one of the answers given. What am I doing wrong? The only thing I can think of is that the load given is NOT the fracture load, however I don't know how/from where to get that load.
A circular specimen of glass is loaded using the three-point bending method. Compute the minimum possible radius of the specimen without fracture, given that the applied load is 4000 N the flexural strength is 65 MPa, and the separation between load points is 35mm.
2. Relevant equations
Flexural Strength = (FL)/(pi*R3) where F is the load at fracture, L is the distance between support points (in mm), and R is the radius of the specimen.
3. The attempt at a solution
Flexural Strength = (FL)/(pi*R3)
so
R = cube root of ((4000N)(0.035m)/(pi*6.5*10^7))
R = 8.818 mm
This is not one of the answers given. What am I doing wrong? The only thing I can think of is that the load given is NOT the fracture load, however I don't know how/from where to get that load.
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