Question

A certain satellite orbiting Earth has a speed of about 17,000 miles/hour. What is its approximate speed expressed to the correct number of significant figures in kilometers/second? One kilometer is about 0.62 mile, and there are 3,600 seconds in an hour.

A.
2.9 km/s
B.
7.6 km/s
C.
38,000,000 km/s
D.
99,000,000 km/s

Answer 1

Answer: B. 7.6km/s

Step-by-step explanation:

Answer 2

B. 7.6 km/s

Step-by-step explanation:

Given:

Speed of the satellite orbiting Earth is,
`v=17000\ miles/hour`

In order to convert the speed from miles/hour to km/s, we need to convert miles to km and hour to seconds.

The conversion factors are:

0.62 miles = 1 km

∴ 1 mile =
`(1)/(0.62)\ km`

1 hour = 3600 s

Now, 17000 miles/hour can be rewritten as:

`17000* (1\ mile)/(1\ hour)\\\\=17000* ((1)/(0.62)\ km )/(3600\ s)\\\\=(17000)/(0.62* 3600)\ km/s\\\\=7.6\ km/s`

Therefore, the speed in km/s is 7.6 km/s.