Physics for Scientists and Engineers, 6e

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Physics for Scientists and Engineers, 6e

• Chapter 1 Physics and Measurement

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In a machine shop, two cams are produced,
one of aluminum, one of iron. Both cams have the
same mass. Which cam is larger?

1. the aluminum cam
2. the iron cam
3. Both cams have the same size.

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Because the density of aluminum is smaller than
that of iron, a larger volume of aluminum is
required for a given mass than iron.
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True or False Dimensional analysis can give you
the numerical value of constants of
proportionality that may appear in an algebraic
expression.

1. True
2. False

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False. Dimensional analysis gives the units of
the proportionality constant but provides no
information about its numerical value. To
determine its numerical value requires either
experimental data or geometrical reasoning. For
example, in the generation of the equation x ½
at2, because the factor ½ is dimensionless, there
is no way of determining it using dimensional
analysis.
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The distance between two cities is 100 mi. The
number of kilometers between the two cities is

1. smaller than 100
2. larger than 100
3. equal to 100

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Because kilometers are shorter than miles, a
larger number of kilometers is required for a
given distance than miles.