2 in.
m = 0.5 slugs
Problem 9.24
9.25. Determine the mass moment of inertia of a steel shaft
that is 5 ft long and has a diameter of 2 in. Express
your answer in lbmft
2
, lbmin
2
, and slugsft
2
.
9.26. Determine the mass moment of inertia of a steel
ball with a diameter of 2 in. Express your answer in
lbmft
2
, lbmin
2
, and slugsft
2
.
9.27. Determine the mass moment of inertia of a 4-in.-
square steel plate. Use Equation 9.13. Express your an-
swer in lbmft
2
, lbmin
2
, and slugsft
2
.
9.28. Determine the specific gravity of the following gasses
by comparing their densities to air at 1.23 kg /m
3. He-
lium: 0.166 kg /m
3
, oxygen: 1.33 kg /m
3
, nitrogen:
1.16 kg /m
3
, natural gas: 0.667 kg /m
3
, and hydrogen:
0.0838 kg /m
3
.
9.29. Calculate the change in the momentum of a car whose
speed changes from 100 km/h to 15 km/h. The car
has a mass of 1000 kg and is moving along a straight
line. Express your answer in SI, BG, and U.S. Cus-
tomary units.
9.30. Calculate the change in the momentum of a 200,000 kg
Boeing 777 whose speed changes from 450 mph to
180 mph. Express your answer in SI, BG, and U.S.
Customary units.
9.31. Kinetic energy is another engineering quantity that is
mass dependent. An object having a mass mand mov-
ing with a speed Vhas a kinetic energy which is equal
to 1/2 mV
2
. In Chapter 13, we will explain the con-
cept of kinetic energy in more detail after we introduce
work. For now, compute the kinetic energy for the fol-
lowing situations: a 1500 kg car moving at a speed of
100 km/h and a 200,000 kg Boeing 777 moving at a
speed of 700 km/h. Express your answers in SI, BG,
and U.S. Customary units.
9.32. Rotational kinetic energy is yet another mass-dependent
engineering quantity. An object having a mass moment
of inertia Iand rotating with angular speed of (rad /s)has a rotational kinetic energy which is equal to I
2
.
Determine the rotational kinetic energy of a steel shaftthat is 5 ft long and has diameter of 2 in. and is rotating
at an angular speed of 100 rpm. Express your answer inSI, BG, and U.S. Customary units.
9.33. Determine the change in mass moment of inertia of an
object that could be modeled as a point mass mwhen
its distance from a center of rotation is doubled.
9.34. Convert the density, specific gravity, and specific
weight data in Table 9.1 from SI units to U.S. Cus-
tomary units. Present your solution in a tabular form
similar to Table 9.1. Do you need to change the values
of specific gravity?
9.35. Convert the density, specific gravity, and specific
weight data in Table 9.1 from SI units to British Grav-
itational units. Present your solution in a tabular form
similar to Table 9.1. Do you need to change the values
of specific gravity?
9.36. A plugged dishwasher sink with the dimensions of
14 in.16 in.6 in. is being filled with water from
a faucet with an inner diameter of 1 in. If it takes
220 seconds to fill the sink to its rim, estimate the mass
flow of water coming out of the faucet.1
2Problem 9.36
Source:Saeed Moaveni9.37. Imagine the plug of the sink described in Problem 9.36
leaks. If it now takes 250 seconds to fill the sink to its
rim, estimate the mass-flow rate of the leak.
9.38. The tank shown in the accompanying figure is being
filled by Pipes 1 and 2. If the water level is to remain
constant, what is the mass-flow rate of water leaving
the tank at Pipe 3? What is the average velocity of the
water leaving the tank? (See figure on next page.)Problems 247
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀