Two blocks A and B are connected to each other by a string and a spring of force constant k, as shown in the figure. The string passes over a frictionless pulley. Block B slides over the horizontal top surface of a stationary block C and block A slides along the vertical side of C both with the same uniform speed. If the coefficient of friction between the surfaces of the blocks is μ and the mass of block A is m, what is the mass of block B?
mμ
Let the mass of block B be M. Since the blocks slide at the same uniform speed, no net force acts on them.
For block B, T=mg
For block A, T=f⇒mg=μMg⇒M=mμ
Hence, the correct choice is (b).