Two wooden blocks are moving on a smooth horizontal surface such that the mass m remains stationary with respect to the block of mass M as shown in the figure. The magnitude of force P is

Acceleration of the system:a=PM+m   ....(i)The FBD of mass m is shown in the figure.Rsin⁡β=ma     ......(i)Rcos⁡β=mg    .....(ii)From Eqs. (ii) and (iii), we geta=gtan⁡βPutting the value of a in (i), we getP=(M+m)gtan⁡β