Q1. A jet of alcohol strikes the vertical plate in Fig. 1. A force F ≈ 425 N is required to hold
the plate stationary. Assuming there are no losses in the nozzle, estimate (a) the mass flow rate
of alcohol and (b) the absolute pressure at section 1. (Answers: (a) 10.3 kg/s; (b) 760 kPa)
Fig.1
Q2. A container of water has a cross-sectional area of 𝐴 = 0.1 m2 . A piston sits on top of the
water (see Fig. 2). There is a spout located 0.15 m from the bottom of the tank, open to the
atmosphere, and a stream of water exits the spout. The cross-sectional area of the spout is 𝐴𝑠 =
7.0 × 10−4 m2 . (a) What is the velocity of the water as it leaves the spout? (b) If the opening
of the spout is located 1.5 m above the ground, how far from the spout does the water hit the
floor? Ignore all friction and dissipative forces. (Answers: (a) 3.28 m/s; (b) 1.81 m)
Fig. 2
Q3. Fire hoses used in major structural fires have an inside diameter of 6.40 cm (Fig. 3).
Suppose such a hose carries a flow of 40.0 L/s, starting at a gauge pressure of 1.6 × 106 N/m2 .
The hose rises up 10.0 m along a ladder to a nozzle having an inside diameter of 3.00 cm. What
is the pressure in the nozzle?
Fig. 3
Q4. The water level in a tank is 15 m above the ground. A hose is connected to the bottom of
the tank, and the nozzle at the end of the hose is pointed straight up (Fig. 4). The tank cover is
airtight, and the air pressure above the water surface is 3 atm gage. The system is at sea level.
Determine the maximum height to which the water stream could rise. (Answer: 46.0 m)
Fig. 4
Q5. In Figure 5, the fluid is gasoline at 20° C at a weight flow of 120 N/s. Assuming no losses,
estimate the gage pressure at section 1. (Answer: 104 kPa)
Fig.5
Q6. A venturi meter, shown in Fig. 6, is a carefully designed constriction whose pressure
difference is a measure of the flow rate in a pipe. Using Bernoulli’s equation for steady
incompressible flow with no losses, show that the flow rate Q is related to the manometer
reading h by
𝑄=
𝐴2
√
√1 − (𝐷2 )
𝐷1
4
2𝑔ℎ(𝜌𝑀 − 𝜌)
𝜌
where 𝜌𝑀 is the density of the manometer fluid.
Fig.6
Q7. For the 40° C water flow in Fig. 7, estimate the volume flow through the pipe, assuming
no losses; then explain what is wrong with this seemingly innocent question. If the actual flow
rate is 𝑄 = 40 m3 /h, compute (a) the head loss in m, (b) the constriction diameter D that
causes cavitation, assuming that the throat divides the head loss equally and that changing the
constriction causes no additional losses, and (c) the flow velocity at the constriction. Given: for
water at 40°C, the vapour pressure is 7375 Pa, and the density is 992 kg/m3 . (Answers: (a) 15
m loss; (b) 25 mm; (c) 23 m/s)
Fig.7
Q8. Air, assumed frictionless, flows through a tube, exiting to the sea-level atmosphere.
Diameters at 1 and 3 are 5 cm, while at 2 is 3 cm. What mass flow of air is required to suck
water up 10 cm into section 2 of Fig. 8? (Answer: 0.037 kg/s)
Fig. 8
Q9. In the spillway flow of Fig. 9, the flow is assumed uniform and hydrostatic at sections 1
and 2. If losses are neglected, compute (a) 𝑉2 and (b) the force per unit width of the water on
the spillway. (Answers: (a) 1.3 m/s, 9.28 m/s; (b) 68.3 kN/m)
Fig.9