Physics question

5. Three blocks rest on a frictionless horizontal surface as shown in the figure below. And m1 = 10 kg and m3 = 15 kg. A horizontal force F = 110 N is applied to block 1 to the right, which generates the acceleration a = 3.3 m/s2 for all three blocks (all blocks move to the right with same acceleration). (a) what is my (b) what is the force between my and m3? 6. A block of mass M1 = 3.0 kg rests on top of second block of mass M2 = 5.0 kg, and the second block M2 sit on a frictionless surface (see the following figure) , if the coefficient of static friction between Mi and M2 is Us =0.21 (a) if a horizontal pulling force F(see figure) is applied to the top block M1, what is the maximum value of F that the two block will not slip apart (moving forward as a whole without being separated) (b) if the force F is applied on the bottom block M2 what will be the maximum F to avoid two blocks slipping apart again? M2 IT