Force and Friction

1) In the above figure A has a mass 40kg and B is of 15 kg and F is 500N parallel to the smooth inclined plane. The system is moving together.(a) Show that the acc of the system is 45/11 m/s²
(b) Show that the least coeff of friction b/w A and B is 9 √3 / 53.

2)
In the above figure , frictiojn exists only b/w wedge and m. The friction coeff being equals to @.Show that the acc of body m relative to the horizontal surface on which wedge slides is mg / [2m +@m +M].