Problems

1.3 The Language of Physics: Physical Quantities and Units

34.

A commemorative coin that sells for $40 is advertised to be plated with 15 mg of gold. Suppose gold is worth about $1,300 per ounce. Which of the following best represents the value of the gold in the coin?

$0.33
$0.69
$3.30
$6.90

35 .

If a marathon runner runs

9.5\,\text{miles}

in one direction,

8.89\,\text{miles}

in another direction and

2.333\,\text{miles}

in a third direction, how much distance did the runner run? Be sure to report your answer using the proper number of significant figures.

$20$
$20.7$
$20.72$
$20.732$

36 .

The speed limit on some interstate highways is roughly

80\,\text{km/h}

. What is this in meters per second? How many miles per hour is this?

$62\,\text{m/s}$ , $27.8\,\text{mi/h}$
$22.2\,\text{m/s}$ , $49.7\,\text{mi/h}$
$62\,\text{m/s}$ , $2.78\,\text{mi/h}$
$2.78\,\text{m/s}$ , $62\,\text{mi/h}$

37 .

The length and width of a rectangular room are measured to be

3.955 \pm 0.005\,\text{m}

3.050 \pm 0.005\,\text{m}\!

. Calculate the area of the room and its uncertainty in square meters.

$12.06 \pm 0.29\,\text{m}^2$
$12.06 \pm 0.01\,\text{m}^2$
$12.06 \pm 0.25\,\text{m}^2$
$12.06 \pm 0.04\,\text{m}^2$