25 Review Problem - Time required to fill a reservoir of water Jhun Vert Sun, 05/03/2020 - 10:03 pm

Problem 25
A reservoir 10 ft. deep is in the form of a frustum of inverted square pyramid with bases of 100 and 90 ft. on a side respectively. How long will it require an inlet pipe to fill the reservoir if the water pours in at the rate of 200 gal. per min.? (One gal. = 231 cu. in.)

## 24 Review Problem - Will the pail hold all the water in the pipe?

Problem 24
A pipe of 3/4-in. inside diameter conducts water from a spring to a house 300 ft. distant. It is desired to empty the pipe after the water has been turned off the spring. Will a 10-qt. pail hold the water? (One gal. = 231 cu. in.)

## 12 Review Problem - Lake for household water supply

Problem 12
The water supply of a district consists of a lake whose surface area is 1000 acres. The number of household supplied with water is 60,000. Supposing each household to use 25 gal. per day, calculate how many days’ supply (to the nearest day below the exact number) is represented by a depth of 1 ft. of water in the lake. (1 acre equals 43,560 sq. ft.)

## SI Base Units

The International System of Units (SI) define the following base units

Meter (m)
The length of the path traveled by light in a vacuum during a time interval of 1/299 792 458 of a second.

Kilogram (kg)
Equal to the mass of the international prototype of the kilogram. The prototype is an alloy of 90% platinum and 10% iridium. It was manufactured in the 1880s and kept with its six official copies in a vault at the BIPM.

Second (s)
The base unit of time. It is the duration of 9 192 631 770 periods of radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.

Ampere (A)
A constant electric current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 meter apart in a vacuum, would produce between these conductors a force equal to 2 × 10-7 newton per meter of length.

Kelvin (K)
The fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

Candela (cd)
Unit for luminous intensity. A source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

Mole (mol)
Unit for quantity of matter. The amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12.