P$2\mathrm{.}55$ Gate $AB$ in Fig. P $2\mathrm{.}55$ is $5$ ft wide into the paper, hinged at $A,$ and restrained by a stop at $B.$ The water is at $20C.$ Compute $($a$)$ the force on stop $B$ and $(b)$ the reactions at $A$ if the water depth $h=9\mathrm{.}5ft.$

P$2\mathrm{.}55$