A cylindrical rod of radius 7mm and Young’s Modulus 70 GPa has a weight F applied to it. The material experiences a strain of 0.2%. What force has been applied?
Young's Modulus is defined as the ratio of stress to strain. E = stress/strain. Stress is the force per unit area, F/A. By substitution, we can see that E = F/(A x strain). Rearranging gives F = E x A x strain. Now it is case of evaluating the expression F = 70x109 x ( π x (7x10-3)2) * 0.2x10-2 = 21551 N. It is important to remember that the strain is given as a percentage, but needs to be evaluated as a ratio of extension to length; i.e. as a decimal.
CW
Related Physics A Level answers
All answers ▸Derive an expression for the centripetal acceleration of a body in uniform circular motion.
Two electrons are a distance r apart, the first electron exerts a force F on the second electron. a) What force does the second electron exert on the first? b) In terms of r, at what distance is the force that the first electron exerts on the second F/9?
What is the function of the control rods in the entire fission reactor proccess?
How might you use sound waves to smash a glass? What are other examples of resonance in everyday life?