Consider an airplane with a jet engine attached to the tail section that expels combustion gases at a rate of $18 \mathrm{~kg} / \mathrm{s}$ with a velocity of $V=300 \mathrm{~m} / \mathrm{s}$ relative to the plane. During landing, a thrust reverser (which serves as a brake for the aircraft and facilitates landing on a short runway) is lowered in the path of the exhaust jet, which deflects the exhaust from rearward to $120^{\circ}$. Find $(a)$ the thrust (forward force) that the engine produces prior to the insertion of the thrust reverser and $(b)$ the braking force produced after the thrust reverser is deployed.

A 16-cm diameter horizontal water jet with a speed of $V_j=20 \mathrm{~m} / \mathrm{s}$ relative to the ground is deflected by a $40^{\circ}$ cone moving to the left at $V_c=10 \mathrm{~m} / \mathrm{s}$. Find the external force, $F$ needed to maintain the motion of the cone. Disregard the gravity and surface shear effects and assume the cross-sectional area of the water jet normal to the direction of motion remains constant throughout the flow.

Repeat the above problem by taking into consideration the weight of the elbow whose mass is $5 \mathrm{~kg}$.

Water flowing steadily at a rate of $0.16 \mathrm{~m}^3 / \mathrm{s}$ is deflected downward by an angled elbow as shown in the figure. For $D=30 \mathrm{~cm}, d=10 \mathrm{~cm}$, and $h=50 \mathrm{~cm}$, find the force acting on the flanges of the elbow and the angle its line of action makes with the horizontal. Take the internal volume of the elbow to be $0.03 \mathrm{~m}^3$ and disregard the weight of the elbow material and the frictional effects.

An 8-cm-diameter horizontal water jet having a velocity of $35 \mathrm{~m} / \mathrm{s}$ strikes a vertical stationary flat plate. The water splatters in all directions in the plane of the plate. How much force is required to hold the plate against the water stream?

The impeller of a centrifugal blower has a radius of 18 cm and a blade width of 6.1 cm at the inlet, and a radius of 30 cm and a blade width of 3.4 cm at the outlet. The blower delivers atmospheric air at $20^{\circ} \mathrm{C}$ and 95 kPa. Disregarding any losses and assuming the tangential components of air velocity at the inlet and the outlet to be equal to the impeller velocity at respective locations, determine the volumetric flow rate of air when the rotational speed of the shaft is 900 rpm and the power consumption of the blower is 120 W. Also determine the normal components of velocity at the inlet and outlet of the impeller.