Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.5The mean free path of a gas, l, is defined as the average distance traveled by molecules between collisions. A
proposed formula for estimating l of an ideal gas is.
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.10The Stokes–Oseen formula [33] for drag force F on a sphere of diameter D in a fluid stream of low velocity V,
density p, and viscosity μ is
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.21Aeronautical engineers measure the pitching moment M_0 of a wing and then write it in the following form for use
in other cases:
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.32A blimp is approximated by a prolate spheroid 90 m long and 30 m in diameter. Estimate the weight
of 20°C gas within the blimp for (a) helium at 1.1 atm and (b) air at 1.0 atm. What might the difference between these
two values represent (see Chap. 2)?
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.33A tank contains 9 kg of CO2 at 20°C and 2.0 MPa. Estimate the volume of the tank, in m^3.
Hanna Tobey
EGMN 301- Homework #1
P1.38In Fig. 1.8, if the fluid is glycerin at 20°C and the width
between plates is 6 mm, what shear stress (in Pa) is required
to move the upper plate at 5.5 m/s? What is the Reynolds number
if L is taken to be the distance between plates?
due-2/1/24
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.40Glycerin at 20°C fills the space between a hollow sleeve of diameter 12 cm and a fixed coaxial solid rod of
diameter 11.8 cm. The outer sleeve is rotated at 120 rev/min. Assuming no temperature change, estimate the torque
required, in N⋅m per meter of rod length, to hold the inner rod fixed.
Hanna Tobey
EGMN 301- Homework #1
P1.57Extend the steady flow between a fixed lower
plate and a moving upper plate, from Fig. 1.8, to the
case of two immiscible liquids between the
plates, as in Fig. P1.57.
due-2/1/24
Hanna Tobey
EGMN 301- Homework #1
due-2/1/24
P1.60Pipelines are cleaned by pushing through them a close-fitting cylinder called a pig. The name comes from the
squealing noise it makes sliding along. Reference 50 describes a new nontoxic pig, driven by compressed air, for
cleaning cosmetic and beverage pipes. Suppose the pig diameter is 5-15/16 and its length 26 in. It cleans a 6-indiameter pipe at a speed of 1.2 m/s. If the clearance is filled with glycerin at 20°C, what pressure difference, in
pascals, is needed to drive the pig? Assume a linear velocity profile in the oil and neglect air drag.
Hanna Tobey
EGMN 301- Homework #1
P1.65The system in Fig. P1.65 is used to calculate the
pressure p1 in the tank by measuring the 15-cm height of
liquid in the 1-mm-diameter tube. The fluid is at 60°C.
Calculate the true fluid height in the tube and the percentage.
error due to capillarity if the fluid is (a) water or (b) mercury.
due-2/1/24