Explore BrainMass


Units are used to measure and describe quantitative data. A unit of measured is a definite magnitude of a physical quantity defined and adopted by convention or by law that is used as a standard for measurement of the same physical quantity. Any other value of that physical quantity can be expressed as a simple multiple of the unit of measurement.

Utilizing and converting units allows scientists and mathematicians to manipulate data by using ratios. There are two main systems of units. International System of Units, S.I units and Engineering Engineering Units, E.E. Units. S.I. units are the modern form of the metric system. It is comprised of seven bases units. This system is international accepted. Only Burma, Liberia and the United States have not adopted this system of units. E.E. units are another system of units used. This system has inconsistencies in converting and requires different conversion factors.

For example, length is a physical quantity. The metre is a unit of length that represents a definite predetermined length. When we say 10 metres, we actually mean 10 times the definite predetermined length called “metre”.

Dimension EE Units SI Units
Time Second (sec) Second (s)
Length Foot (Ft) Metre (m)
Mass Pound mass (Lbm) Kilogram (Kg)
Force Pound Force (Lbf) Newton (N)


Scarcity of Potable Water

In the world there is a scarcity of potable water. How might we solve this problem in the future? if you have any idea i am happy to learn from you and if you have internet site or books let me know with it i can learn more about the subject. Thanks.

Determining speed and direction of an aircraft

A. The pilot of an aircraft wishes to fly due west in a 50 km/h wind blowing towards the south. The speed of the aircraft, relative to the air is 100 km/h. In what direction should the aircraft head? (Answer in units of degrees from due East, with counterclockwise positive, within the limits of -180 degrees to +180 degrees).

Electromagnetiam: Force between two wires carrying current

Two long, straight wires are separated by a distance of 31.7 cm. One wire carries a current of 2.95 A, the other carries a current of 4.32 A. Calculate the force per meter exerted on the 2.95 A wire. Calculate the force per meter exerted on the 4.32 A wire.

Unit Conversions Quantities in Standard Units

1. Write the following quantities in standard units. (a) 0.66 Ms (b) 3.5 km (c) 27 mg (d) 125 cm 2. Compute, in centimeters and meters, the height of a basketball player 6 ft 4 in tall. 3. Is the following statement reasonable? It took 380 L of gasoline to fill up the car's tank. 4. A car trav

Permeability of Wood Species

I can see that a Darcy's law permeability equation exists and is as follows: k = (volume of liquid x length of specimen)/(time of flow x cross-sectional area of specimen x deltaP) In this equation, there are 2 parameters that I do not understand 1) When the equation refers to the "time of flow" (t) what is meant by that?

Water Usage and Loose of Depth in Lake

An average family of four uses roughly 1200 liters of water per day. How much depth would a lake lose per year if it uniformly covered an are of 50 square kilometers and supplied a local town with a population of 40,000 people? Consider only population uses, and neglect evaporation and so on.


Please convert them (a) 456 cal to joules (b) 22.3 j to Calories (c) 234 kj to Calories (d) 12.4 Cal to joules -Calculate the amount of heat required to heat a 3.5-kg gold bar from 21 degrees celcius to 67 degrees celcius. -If 57 j of heat are added to an aluminum can with a mass of17.1 g, what is its tem

Integral and Unit Conversion

See attached file for full problem description. 5. Express the units of in meters, kilograms, seconds, and Amperes (the basic SI units). Then do the same for... Finally, show that the numerical value of is equal to the speed of light. 6. Show that, for any vector F, where S is the surface bounding the volume V.

Conversion questions

1. Convert the following numbers to SI: a. 56.8 in = b. 1 year = c. 34.8 atm = d. 8.3 Btu/min = e. 38.96 ft/min f. 98.6 furlongs per fortnight g. 34.5 in pdl h. 15.8 gal/min 2. Perform the following conversions: a. 34.589 Pa to psia b. 34.6 m/s to mph c. 89.6 L to m3 d. 68.4 in3 to ft3 e. 964 slug to lbm f.

The Metric System and Conversion

1) In a few years you will start buying gasoline in liters instead of gallons. How many liters would you order to fill a tank of 10.6 gallon capacity? 2) Measure the size of coins and a dollar bill in English and in the Metric system. 3) Brand X advertises 16.4 mg of "tar" in each of its cigarettes. How many grams of "ta

Linear Momentum and Collisions - two questions

A.) In a collision, the time of impact is 36.02 milliseconds and the average force is 518.83 newtons. To the nearest hundredth of a joule*sec what is the impulse? b.) If the mass of the ball is 3.34 and its velocity before collision is 3.86 m/s, to the nearest hundredth of a m/s, what is its velocity after collision?

Wave patterns

You have an aluminum rod that has a F=400N with a Length of 2m. Aluminum's density (rho) is 2.71 x 10^3 kg/m. It has a diameter of 0.5 mm so use I2r. Find v, velocity.

Calculating mass and thickness

The average density of blood is 1.06 x 103 kg/ m3. If you donate a pint of blood to the Red Cross, what mass of blood have you donated, in grams? (1 pt = 1/2 L, 1 L = 1000 cm3) a. 530 g b. 0.530 g c. 5.30 x 103 g d. 5.30 x 105 g e. 5.30 g The l

Calculating Cost/Gallon

Question: If kerosene costs 130 passi per liter, and one dollar buys 227, what is its cost in dollars per gallon? [1.00 gallon = 3.79 liters] a. $2.17 per gallon b. $6.62 per gallon c. 15 cents per gallon d. 46 cents per gallon

Miles to Meters Conversion

Sixty miles/hour is about how many meters/second? a. 96 b. 112 c. 1.6 d. 27 e. 37 How many significant figures are in 0.0037010? I think their are seven significant figures is that correct?

Angstrom Unit

Given 1 angstrom unit = 10 ^-10 m and 1 fermi = 10 ^--15 m , what is the a. 1 angstrom = 10^5 fermi b. 1 angstrom = 10^-5 fermi c. 1 angstrom = 10^-25 fermi d. 1 angstrom = 10^25 fermi e. 1 angstrom = 10^-15 fermi

Metric Conversions : Speed and Kinetic Energy of the Eurasion Plate

The Eurasian plate, has a mass of 2.5*10^22kg and travels over the Earth's interior at 7 mm yr^-1. Express this speed in m s^-1(note there are 3.15*10^7 seconds in a year). Using the equation for kinetic energy Ek=1/2mv^2 (where m is mass and v is speed) calculate the kinetic energy of the Eurasian plate, give the final answer


Two snowcats tow a housing unit to a new location at McMurdo Base, Antarctica, as shown in Fig. 4-43. The sum of the forces FA and FB exerted on the unit by the horizontal cables is parallel to the line L, and FA = 4900 N....See Attached

Relating Power to Distance and Speed: Conversion Problems

STEP1: A 240 horsepower car that weighs 4300 lbs beginning at a stop travels 1/10 of a mile. At optimum performance, what is the maximum speed in MILES per HOUR the car can reach? What is the speed in Mi/Hr at 1/15 of a mile? STEP2: In the same car, how many FEET have been traveled (at max performance) when the car reaches th

Temperature Scales

The world seems to think that a new temperature scale is needed, the NurAn degree. On this scale it is decided that water will freeze at 17 degrees NurAn and boil at 167 degrees NurAn. On this scale, what is the body's average core temperature? How about absolute zero? One day a nurse's temperature is measured as 75 degrees NurA

Vector A in polar coordinates, vector B in unit vectors

See attached file. Vectors A in polar coordinates and vector B with unit vectors are given. Find a vector sum and a vector difference. Ignore units. Vector A= 5 units at 53 degrees, and B= 5 i - 2 j in which i and j are unit vectors in x and y directions respectively. PART a. Show A and B and vector sum C in a polygon

Working with astronomical units.

Astronomical Unit of earth to sun is @ 1.50 x 10^8 km. Speed of light is about 3.0 x 10^8 m/s. Express the speed of light in terms of (AU) per minute.


I haven't been in school for 20 years and I have forgotten how to set up a math equation to figure out conversions (US to Metric).

Express physical quantities in different units of measurement.

1) A sphere has a radius 1.500m Find its volume in cm^3. Find its suface area in m^2 and in mm^2? 2) A truncated right circular cone has dimensions: upper base diameter =1.50cm lower base diameter = 4.00cm height = 6.00cm Find its volume in cm^3, m^3, mm^3 3) a person walks 5km in 1,5hr. What is the speed in mi