#### Linear Momentum: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

##### Example Problem 1

The aluminum elbow is bolted to a pipe, which is not shown. The bolts provide a force that anchors the elbow in place. What are the x- and y-components of this anchoring force? The diameters of the entrance and exit are *D _{1}* = 10 cm and

*D*= 5 cm. The mass of the elbow is

_{2}*m*= 2.4 kg. The mass of the water inside of it is

_{e}*m*= 3 kg. The volumetric flow rate of the water is

_{w}*Q*= 15 L/s. The gage pressure of the water entering the elbow is

*P*= 30 kPa. The water exits the elbow as a free jet.

_{1}##### Example Problem 2

How much reverse thrust is developed? The diameter of the fan is 2 m. The engine is drawing in a mass flow rate of air of 500 kg/s. Air flows through the engine and is deflected at an angle of 60 degrees from the horizontal. The velocity exiting through the thrust reversers (V_{2}) is 3 times the magnitude of the velocity entering the engine (V_{1}).