Select the correct answer.

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 :

To determine the speed of a satellite orbiting Earth in kilometers per second, given its speed in miles per hour, you can follow these steps:

1. Convert the speed from miles per hour to kilometers per hour:
- We know that 1 mile is approximately equal to 0.62 kilometers.
- Therefore, if the satellite is traveling at 17,000 miles per hour, we can convert this speed to kilometers per hour by multiplying by the conversion factor:

[tex]\[ 17,000 \, \text{miles/hour} \times 0.62 \, \text{km/mile} = 10,540 \, \text{km/hour} \][/tex]

2. Convert the speed from kilometers per hour to kilometers per second:
- There are 3,600 seconds in one hour.
- To convert the speed from kilometers per hour to kilometers per second, we divide the speed in kilometers per hour by the number of seconds in an hour:

[tex]\[ 10,540 \, \text{km/hour} \div 3,600 \, \text{seconds/hour} \approx 2.9277777777777776 \, \text{km/second} \][/tex]

3. Round the result to the appropriate number of significant figures:
- Considering the significant figures from the original speed of 17,000 miles/hour (2 significant figures), we round the result to 2 significant figures:

[tex]\[ 2.9277777777777776 \, \text{km/second} \approx 2.9 \, \text{km/second} \][/tex]

Therefore, the satellite's speed in the correct number of significant figures is approximately 2.9 km/s.

The correct answer is:
A. 2.9 km/s

Other Questions