A cylinder 3 m in diameter and 4 m long retains water one side as shown in the below figure. If the weight of the cylinder is 2000 kgf, the vertical reaction at A is

ANS:B - 5,863 kgf

Reaction = vertical force by water on A+2000kg
Vertical force = wt of water in a volume[volume here is vertically upward projected portion of water without the semicylindrical portion]
Vertical force = 1000 * vol = 1000 * [3 * 1.4 * 4 - 0.5 * 3.14 * 3^(2) * 4/4 = 1000 * [18 - 14.137].
= 3863kg force.
Then the reaction = 3863 + 2000 = 5863kg.