Water flows through two sections of the vertical pipe shown in Fig. $\mathrm{P} 8.95$. The bellows connection cannot support any force in the vertical direction. The 0.4-ft-diameter pipe weights 0.2 $1 \mathrm{b} / \mathrm{ft}$ and the friction factor is assumed to be $0.02 .$ At what velocity will the force, $F$, required to hold the pipe be zero?