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A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has speed of 20 cm/s. How much work is needed to stop it? |
1 J 3 J 30 J 2 J |
3 J |
Work to be done = Change in kinetic energy KEi = \(\frac{1}{2}mv^2 + \frac{1}{2} Iw^2\) = \(\frac{3}{4}mv^2\) = 3 J KEf = zero Work done : W = 3 J |
