Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

shows a value of 9.45 kg after 30 minutes, what is the

fuel consumption of the lawn mower in gallons per

hour?

Problems 249

To l awn mo wer

Tank

9.48. In a water bottling process, one-liter bottles are filled

through a system that provides filtered water to each

bottle at rate of 0.7 lbm/s. How long would it take to fill

a bottle? How many bottles can be filled in one hour if

the system can fill 20 bottles simultaneously with a re-

quired time of 3 seconds to move away the filled bottles

and bring in the new batch of empty bottles?

9.49. Water is available at a rate of 400 gallons /min to a

small apartment complex, consisting of four units. If at

a given time, units 1, 2, and 3 are consuming 18 lbm/s,

14 lbm/s, 16 lbm/s, respectively, how much water is

available to unit 4? Express your answer in

gallons /min, ft

3

/s, m

3

/s, lbm/s, and kg /s.

9.50. A hydrometeris a device which uses the principle of

buoyancy to measure the Specific Gravity (S.G.) of a

liquid. Design a pocket-sized hydrometer that can be

used to measure S.G. for liquids having 1.2 S.G.

1.5. Specify important dimensions and the mass of the

device. Write a brief report to your instructor explain-

ing how you arrived at the final design. Also include a

sketch showing the calibrated scale from which one

would read S.G. In addition, construct a model and

attach the scale to the working model. To keep things

simple, assume that the hydrometer has a cylindrical

shape.

“Education is what remains after one has forgotten everything he learned in school.”

—Albert Einstein(1879 –1955)

Problem 9.47

Problem 9.50

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