As shown to the right, two blocks with masses m and M `(Mgtm)` are pushed by a force F in both Case I and Case II. The surface on which blocks lie, is horizontal and frictionless. Let `R_I` be the force that m exerts on M in case I and `R_(II)` be the force that m exerts on M in case II. Which of the following statements is true?

Options

A. `R_(I)=R_(II)` and is not equal to zero or F
B. `R_(I)=R_(II)=F`
C. `R_(I)ltR_(II)`
D. `R_(I)gtR_(II)`

Answer

C

Explanation

Accelerationo of all blocks in both cases is the same and is `a=(F)/(m+M)`
In case I: required normal reaction `R_(I)` is equal to net force on block of mass m
`R_(I)=ma`
In case II: required normal reaction `R_(II)` is equal to net force on block of mass M.
`R_(II)=Ma`
Hence `R_(II)gtR_(I)`