A 2-cm-diameter, 20-cm-long bar of an acetal polymer (Figure) is loaded on one end and is...

A 2-cm-diameter, 20-cm-long bar of an acetal polymer (Figure) is loaded on one end and is expected to survive one million cycles of loading, with equal maximum tensile and compressive stresses, during its lifetime. What is the maximum permissible load that can be applied?