$4\mathrm{.}81$ A $30$ reducing elbow is shown. The fluid is water. Evalu$-$

ate the components of force that must be provided by the adjacent

pipes to keep the elbow from moving.

P$4\mathrm{.}874\mathrm{.}124$ The circular dish, whose cross section is shown, has an

outside diameter of $0\mathrm{.}20$ m $.$ A water jet with speed of $35\frac{m}{s}$

strikes the dish concentrically. The dish moves to the left at

$15\frac{m}{s}.$ The jet diameter is $20$ mm $.$ The dish has a hole at its cen$-$

ter that allows a stream of water $10$ mm in diameter to pass

through without resistance. The remainder of the jet is deflected

and flows along the dish. Calculate the force required to maintain

the dish motion. P$4\mathrm{.}110$

$4\mathrm{.}111$ A stream of air at standard conditions from a $50$ mm diam$-$

eter nozzle strikes a curved vane as shown. A stagnation tube con$-$

nected to a water$-$filled U$-$tube manometer is located in the nozzle

exit plane. Calculate the speed of the air leaving the nozzle. Esti$-$

mate the horizontal component of force exerted on the vane by the

jet. Comment on each assumption used to solve this problem.

P$4\mathrm{.}111$