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The centripetal force F acting on particle moving uniformly in a circle may depend upon mass (m), velocity (v) and radius (r) of the circle. Derive the formula for F using the method of dimensions. |
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Answer» Let F = K ma vb rc Where K is the dimensionless constant of proportionality and a, b, c are the powers of m, v and r respectively to represent F. Writing the dimensions of various quantities in equation (ii), we get [M1L1T-2] = [M]a [LT-1]b [L]c = Ma Lb T-b Lc = Ma Lb + T-b Applying the principle of homogeneity of dimensions we get a = 1, b +c = 1 -b = -2 or, b = 2 From (ii) c = 1 -b = 1 -2 = -1 Putting the values of a,b and c, in (i) we get F = K m1 v2 r-1 or, F =K mv2/r |
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