A $2-$m$-$long, $4-$cm$-$diameter shaft rotates inside an equally long $4\mathrm{.}02-$ cm $-$diameter cylinder. If SAE$-10$W

oil at $25C$ fills the gap between the concentric cylinders, determine the torque and horsepower needed

to rotate the shaft at $1200$ rpm $.$

How long would it take a small wave to travel under $22C$ water a distance of $800$ m $?$

The coefficient of thermal expansion ${}_T$ allows the expansion of a liquid to be determined using the equation

$H={}_{T}AAT.$ Calculate the decrease in $2m^3$ of $40C$ water if the temperature is lowered by $10C.$ What

pressure would be needed to cause the same decrease in volume? Use $=3\mathrm{.}8{10}^{-4}{K}^{-1}.$

Estimate the pressure inside a droplet of $20C$ water and a bubble of $20C$ water if their diameters are

$($a$)40m$

$($b$)20m$

$($c$)4m$

Mercury makes an angle of $130$ with respect to the vertical when in contact with clean glass. How far

will mercury depress in a clean, $10-m-$diameter glass tube if ${}_{Hg}=0\mathrm{.}467\frac{N}{m}.$

A steel needle of length $L$ and radius $r$ will float in water if carefully placed. Write an equation that relates

the various variables for a floating needle assuming a vertical surface tension force.

Two kilograms of $40C$ air is contained in a $4-m^3$ volume. Calculate the pressure, density, specific

volume, and specific weight.

The temperature outside a house is $-20C$ and inside it is $20C.$ What is the ratio of the density of the out$-$

side air to the density of the inside air? Would infiltration, which results from cracks around the windows,

doors, and siding, etc., occur even with no wind causing a pressure difference?

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