A steel block of 10kg rests on a horizontal floor as shown. When...

A steel block of $10kg$ rests on a horizontal floor as shown. When three iron cylinders are placed on it as shown, the block and cylinders go down with an acceleration $0 . 2m{s}^{- 2} .$ The normal reaction ${R}^{'}$ by the floor if mass of the iron cylinders are equal and of $20kg$ each is \left(\text{in}N\right)$,</p><p>[Take g = 10m{s}^{- 2} and {\mu}_{s} = 0 . 2]$