The speed of a block traveling on a horizontal frictional surface changes from v_i = 16 m/s to v_f = 10.5 m/s in a distance of d = 9.5 m.

a) How long in seconds did it take for the block to slow by this amount, assuming the acceleration is constant?

b) If the block has a mass of 1 kg, what is the average power supplied to the block by friction while it slows from 16 m/s to 10.5 m/s?

c) What is the coefficient of kinetic friction between the block and surface _k?