. A 1212} kg box is pushed along a horizontal surface by a 24 N force as illustrated in the diagram. The frictional force (kinetic) acting on the 12.9 kg box is 5.0 N. 245] 4.0 kg a. What is the acceleration of the 12.0 kg hos? b. It the 12.13 kg box then runs into a 4.0 kg hos that increases the overall friction by 312} N. what is the new acceleration