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Physics
A uniform disc of mass m and radius R is projected horizontally with velocity v₀ on a rough horizontal floor so that it starts off with a purely sliding motion at t = 0. After t₀ seconds, it aquires a purely rolling motion as shown in figure (i) Calculate the velocity of the center of mass of the disc at t₀. (ii) Assuming the coefficient of friction to be , calculate t₀. Also calculate the work done by the frictional force as a function of time and the total work done by it over a time t much longer than t₀.
Chemistry
Identify (A) to (D) in the following series of reactions.
Mathematics
If f(x) = z x -2 and g(x) = f[f(x)], then g' (x) = ....................for x > 20.