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PHYS-2325: University Physics-I
Khalid Bukhari
Ch-14
SOLUTION TO SIMILAR PROBLEMS
Chapter-14: FLUID MECHANICS
1.
A 50.0-kg woman balances on one heel of a pair of high-heeled shoes. If the heel
is circular and has a radius of 0.500 cm, what pressure does she exert on the floor?
2.
What is the total mass of the Earth’s atmosphere? (The radius of the Earth is 6.37 
106 m, and atmospheric pressure at the surface is 1.013  105 N/m2.)
3.
Assume the density of seawater is 1,024 kg/m3 and the air above exerts a pressure
of 101.3 kPa. At a depth of 1000 m, what force must the frame around a circular
submarine porthole having a diameter of 30.0 cm exert to counterbalance the force
exerted by the water?
4.
Normal atmospheric pressure is 1.013  105 Pa. The approach of a storm causes
the height of a mercury barometer to drop by 20.0 mm from the normal height. What is
the atmospheric pressure? (The density of mercury is 13.59 g/cm3.)
PHYS-2325: University Physics-I
Khalid Bukhari
Ch-14
5.
The gravitational force exerted on a solid object is 5.00 N. When the object is
suspended from a spring scale and submerged in water, the scale reads 3.50 N (Fig.
P14.22). Find the density of the object.
6.
A cube of wood having an edge dimension of 20.0 cm and a density of 650 kg/m3
floats on water. (a) What is the distance from the horizontal top surface of the cube to
the water level?
7.
In P6, what mass of lead should be placed on the cube so that the top of the
cube will be just level with the water?
PHYS-2325: University Physics-I
Khalid Bukhari
Ch-14
8.
Water flows through a fire hose of diameter 6.35 cm at a rate of 0.012 0 m3/s. The
fire hose ends in a nozzle of inner diameter 2.20 cm. What is the speed with which the
water exits the nozzle?
9.
Water moves through a constricted pipe in steady, ideal flow. At one point as
shown in Figure 14.16 where the pressure is 2.50  104 Pa, the diameter is 8.00 cm. At
another point 0.500 m higher, the pressure is equal to 1.50  104 Pa and the diameter is
4.00 cm. Find the speed of flow in the upper section.
PHYS-2325: University Physics-I
10.
Khalid Bukhari
Ch-14
A hypodermic syringe contains a medicine having the density of water (Fig. P14.49).
The barrel of the syringe has a cross-sectional area A = 2.50  10–5 m2, and the needle has a crosssectional area a= 1.00  10–8 m2. In the absence of a force on the plunger, the pressure
everywhere is 1 atm. A force F of magnitude 2.00 N acts on the plunger, making medicine squirt
horizontally from the needle. Determine the speed of the medicine as it leaves the needle’s tip.
11. A jet of water squirts out horizontally from a hole near the bottom of the tank shown in Figure. If
the hole has a diameter of 3.50 mm, what is the height h of the water level in the tank?