1. a block of mass m is placed on a surface with a vertical cross section given by y=x³/6 . if the coefficient of friction is 0.5 the maximum height above the grond at which the block can be placed without slipping is

First you differentiate the given equation w.r.t. ‘x’ that will give you tangent of angle that we called coefficient of friction.
Second, After getting the value of ‘x’, you just put this value in main euation, you will get the maximum value for ‘y’.

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