InterviewSolution
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InterviewSolution
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wire sstress x strain.Q19 Show that strain energy per unit volume of strained2to an ammeter. Derive ne |
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Answer» We know, Young's modulus is the ratio of stress to strain. e.g., Y = stress/strain.if we assume a wire of length L, area of cross section A is fixed at one end and stretched by suspended a load M from the other end due to this extension of wire is x. so, Young's modulus of wire , Y = FL/Ax or, F = YAx/L we know, workdone , W = F.dx so, W = (YAx/L)dxor, W = 1/2 × YAx²/L W = 1/2 × {YAx/L} × x W = 1/2 × F × x hence, Work done = 1/2 × load × extension now, potential energy = workdone by external applied force = 1/2 × load × extension.so, strain energy = 1/2 × load × extensionnow, strain energy per unit volume = 1/2 × load × extension/volume = 1/2 × load × extension/(cross section area × length)= 1/2 × (load/cross section area) × (extension/length)= 1/2 × stress × strain hence, energy per unit volume = 1/2 × stress × strain |
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