Question

the mass of a piece of copper wire. the true mass of the wire is the mean of two measurements for each student are as follows:

	student a	student b	student c
trial 2	1.978 g	1.968 g	2.002 g
average value	1.971 g	1.970 g	2.001 g

1. which students data is the most precise? provide evidence that supports your identification. 2
2. complete the following conversions using dimensional analysis. you must use the conversions in the box to earn full credit. all units must be shown to earn full credit.

12 in = 1 ft
1 in = 2.54 cm
1000 m = 1 km
1 min = 60 sec
1 hour = 60 min
a) how many centimeters are equal to 8.52 feet? 3
b) a speed boat is traveling at a speed of 42.5 km/hr. what is this speed in m/sec? 4

Explanation:

Step1: Convert feet to inches

We know that 1 ft = 12 in. So for 8.52 ft, the number of inches is $8.52\times12$ in.
$8.52\times12 = 102.24$ in

Step2: Convert inches to centimeters

Since 1 in = 2.54 cm, then for 102.24 in, the number of centimeters is $102.24\times2.54$ cm.
$102.24\times2.54=259.6896\approx259.69$ cm

Step3: Convert km/hr to m/sec for speed - boat speed

First, convert kilometers to meters. We know that 1 km = 1000 m, so 42.5 km = $42.5\times1000$ m = 42500 m.
Second, convert hours to seconds. Since 1 hour = 60 min and 1 min = 60 sec, then 1 hour = $60\times60$ sec=3600 sec.
The speed in m/sec is $\frac{42500}{3600}\approx11.81$ m/sec

Answer:

a) 259.69 cm
b) 11.81 m/sec