The two blocks, m= 10 kg and M = 50 kg are free to move as shown. The coefficient of static friction between the blocks is 0.5 and there is no friction between M and the ground. A minimum horizontal force F is applied to hold m against M that is equal to -

Options

A. 100 N
B. 50 N
C. 240 N
D. 180 N

Explanation

Limiting condition for m to not slip in vertical downward direction, `mg-muN`
`rArrN=(mg)/(mu)=(100)/(0.5)=200N`
Same normal force would accelerate M, thus
`a_(M)=(200)/(50)=4m//s^(2)` Taking m+M as system
`F=(m+M).4=240N`