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Quiz 1 ( ME 241 Fluid Mechanics Fall 2005)
Total 100 points. Time allowed 45 minutes
Please write your NAME here:
1. Give one example of each of the following: a Newtonian fluid,
a non-Newtonian fluid, a fluidthat is much denser than water, a
fluid that is much more viscous than water. [5 pts]
2. Write down the dimensions of the following physical
quantities using the M,L,T notation (a)coefficient of surface
tension (b) kinematic viscosity. [5 pts]
3. Which (if any) of the following properties of a fluid would
be different if measured on themoon (a) Density (b) Specific
Gravity (c) Specific weight (d) Dynamic Viscosity (e)
Kinematicviscosity. [5 pts]
4. Which of the following quantities are dimensionless (a)
specific weight (b) specific gravity (c)coefficient of surface
tension (d) kinematic viscosity (e) contact angle [5 pts]
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5. A helium party balloon has a volume of 20 cubic centimeter.
What is the tension in the stringholding it down if the weight of
the balloon fabric is negligible. (density of air is 1.23 andthat
of Helium is 0.17 both in kg per cubic meter). [20 pts]
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7. An iceberg is floating in the sea (salt water) with 97% of
its volume submerged. It driftsthrough an estuary and into a fresh
water river where it floats with only 1% of its volumeabove the
waterline. What is the density of the sea water and the density of
the ice if thespecific gravity of the river water is 1 ? [20
pts]
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8. As you blink, a thin film of fluid (tears) lubricates the
motion of your eyelid over the eyeball.Humans on the average blink
once every 4 seconds and each such twinkling of an eye lastsabout
100 milli seconds. During this time, the eyelid approximately
travels a distance equalto about half the circumference of the eye
ball and back. Take 1.0 cm as the radius of the eyeball and 1 cP
(cP = centi Poise = 1/100 th Poise, 1 Poise = 1 dyne / cm, the CGS
unit of
viscosity) as the kinematic viscosity of water. If the gap
between the eyelids and the cornea is50 micron (1 micron = 106 m)
and the cornea (the transparent part of the eyeball throughwhich
you can see the iris) is a circular patch of diameter 3.0 mm,
estimate the maximumtangential force on the cornea during blinking.
[20 pts]
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USE THE FOLLOWING PAGES FOR ROUGH WORK
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