phys Q 1

According to the text, on what are science and engineering based?

measurements and comparison

Complete the following statement:  The standard meter is defined in terms of the speed of light because

it is a universal constant.

The text uses SI units, such as the meter or the kilogram.  Which one of the following phrases is the best translation for the French phrase for which “SI” is the abbreviation?

International System of Units

Which of the following units is not an SI base unit?

slug

In the International System of Units, mass is measured using which of the following units?

kilograms

In the International System of Units, length is measured using which of the following units?

meters

Express 0.00592 in scientific notation.

5.92 × 10^-3

The ratio (1-millimeter/ 1-kilometer) equals

10 ^{-6 m}

The energy content of food is reported in Calories, where 1 Calorie = 1000 kilocalories and 1 kilocalorie = 4186 J.  How many joules are in a drink that contains 140 Calories?

5.9 × 10⁸ joules

Which one of the following statements concerning unit conversion is false?

Units have no numerical significance, so 1.00 kilogram = 1.00 slug.

Which one of the following pairs of units may not be added together, even after the appropriate unit conversions have been made?

seconds and slugs

How many meters are there in 12.5 kilometers?

12 500

Express the quantity 12.5 meters in kilometers?

0.0125 km

If one inch is equal to 2.54 cm, express 9.68 inches in meters.

0.246 m

By international agreement, the standard meter is currently defined by which of the following methods.

The standard meter is the length of the path traveled by light in a vacuum during a specific time interval.

The textbook discusses order-of-magnitude estimates that scientists and engineers often use.  Consider the distance between New York, NY and Los Angeles, CA.  What is the order of magnitude of this distance?

3

In 1983, the current definition of the standard meter was adopted at the 17th General Conference on Weights and Measures.  In addition to the length standard adopted, what other significant action was taken?

The speed of light was defined to be exactly 299 792 458 m/s.

How is the standard unit of time, the “second,” defined in the International System of Units?

using a high precision cesium (atomic) clock

The period of rotation of the Earth is one day.  The time of one day was compared with that measured by a cesium clock.  How much variation was observed in the period of rotation of the Earth during the four year interval shown in the text?

The variation was within about two milliseconds.

The international standard kilogram is a cylinder that is housed under special conditions near Paris, France.  The cylinder is made from what kind of material?

platinum-iridium alloy

The second mass standard is that of the carbon-12 atom.  What is the unit associated with this second mass standard?

atomic mass unit (u)

When we measure physical quantities, the units may be anything that is reasonable as long as they are well defined.  It’s usually best to use the international standard units.  Density may be defined as the mass of an object divided by its volume.  Which of the following units would probably not be acceptable units of density?

gallons/liter

Complete the following statement: The ratio (1-milligram/ 1-kilogram) is equal to

10 ^{-6 g}

Which one of the following choices is equivalent to 8.0 m²?

8.0 × 10⁴ cm²

A certain physical quantity, R, is calculated using the formula: R = 4a2(b  – c) where a is a speed (a distance traveled per unit time interval) and b and c are distances.  What is the SI unit for R?

m³/s

Express 61 mg in kilograms

0.000061 kg

A section of a river can be approximated as a rectangle that is 48 m wide and 172 m long.  Express the area of this river in square kilometers.

8.26 × 10-3 km²

Express the following statement as an algebraic expression: “There are 264 gallons in a one cubic meter container.”  Let G represent the number of gallons and M represent the number of one cubic meter containers. 

G = M/264

Given that one inch is equal to 25.4 mm.  How many feet equal 21 m?

68.9 ft

Given that one inch is equal to 25.4 mm.  How many meters equal 11.3 ft?

3.4 m

Approximately how many seconds are there in a century?

3.2 × 10⁹ s

A glacier is receding at a constant rate of 0.4 cm per day.  After 3.0 years, by what length has the glacier receded?  Express your answer in meters.

4.38 m

A unit of length used in astronomy and in the area of physics called special relativity is the light-year.  The light-year (ly) is defined as the distance that light travels in vacuum in a one year interval of time.  Estimate the order of magnitude of the number of kilometers in one light-year.

13

Consider each of the following comparisons between various length units.  Which one of these comparisons is false?

1 foot < 10 cm

In an atomic clock there are approximately 9.193 × 10⁹ oscillations of the specified light emitted by cesium-133 atoms.  The text describes the typically accuracy of atomic clocks in terms of two atomic clocks differing by only one second in 6000 years.  Assume one of the clocks gains one second in six thousand years, approximately what is the change in the number of oscillations of the light each second?

+18.11 oscillations/s

Consider each of the following comparisons between various time units.  Which one of these comparisons is false?

1 ns > 1000 µs

Gold can be compressed to a thickness of 1.0 micron to make gold leaf.  If each cubic centimeter of gold has a mass of 19.32 g, what mass of gold leaf in grams is needed to cover a statue with a total surface area of 12 m²?  Note: a micrometer is sometimes called a micron.

1.6 g