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A disc of mass 100 g rolling without slipping on a horizontal surface with a velocity of 10 cm/s. Calculate its total energy? |
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Answer» M = 100g M = .10 kg u = 10 cm/s u = 10 x 10-2 m/s Total energy = Rotational kinetic energy = \(\cfrac12\) Iw2 + \(\cfrac12\) mv2 \(\because\) I = \(\cfrac12\) mR2 = \(\cfrac12\) x \(\cfrac12\) mR2 x w2 + \(\cfrac12\) x mv2 \(\because\) v = Rw = \(\cfrac14 mv^2\) + \(\cfrac12 mv^2\) = \(\cfrac{mv^2+2mv^2}4\) = \(\cfrac{3mv^2}4\) = \(\cfrac{3\times.10\times(10\times10^{-2})^2}4\) = \(\cfrac{3\times.10\times100\times10^{-4}}4\) = 7.5 x 10-4 J |
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