Two Masses Are Connected by a String Which Passes Over

Multiple Choice

Two masses are connected by a string which passes over a pulley with negligible mass and friction. One mass hangs vertically and one mass slides on a frictionless horizontal surface. The horizontal surface has a coefficient of kinetic friction of 0.2. The vertically hanging mass is 4.00 kg and the mass on the horizontal surface is 6.00 kg. The acceleration of the 4.00 kg mass is

A) 1.98 m/s² down
B) 2.74 m/s² down
C) 4.88 m/s² down
D) 6.73 m/s² down
E) 7.84 m/s² down