Hii can you help me with these questions please I know the answers but I don't know how to do them thanks ??

18. Two blocks of mass mi = 2 kg and mass m2 = 7 kg are wedged up against one another and against a wall by a horizontal force F. Solve each part just using the variables to get an expression for the unknown in terms of variables before plugging in wall numbers. m1 m 2 a) What is the coefficient of static friction between ml and m2 (call F this us1) and between m2 and the wall (call this us2) if the MINIMUM force Fmin required to keep the blocks from breaking loose and sliding under the influence of gravity is Fmin = 25 N? b) The force F is decreased to 20 N. The blocks break loose and begin to fall. If the coefficient of kinetic friction between ml and m2 AND between m2 and the wall are uk1 = 0.15 and Mk2 = 0.9 respectively, what are the accelerations of ml and m2? Note that they will not be the same. c) Why are the accelerations different?18. a) us1 = 0.784, us2 = 3.5 b) al=8.3m/s', a2=7.7m/s2 c) The coefficient and force of kinetic friction acting on each of the blocks is different and this causes the acceleration of each block to be different