To convert the speed of a car from meters per second (m/s) to kilometers per hour (km/hr), follow these steps:
1. Understand the relationship between meters and kilometers, and seconds and hours:
- 1 kilometer (km) is equal to 1,000 meters (m).
- 1 hour (hr) is equal to 3,600 seconds (s).
2. Convert the speed from meters per second to kilometers per hour:
- To convert from m/s to km/hr, multiply the speed in m/s by the factor that converts meters to kilometers and seconds to hours.
3. Use the conversion factor:
- The conversion factor from m/s to km/hr is 3.6 because
[tex]\[
\text{1 m/s} = \text{1 m} \times \frac{\text{1 km}}{\text{1000 m}} \times \frac{\text{3600 s}}{\text{1 hr}} = 3.6 \text{ km/hr}
\][/tex]
4. Calculate the conversion:
- Given speed = 20 m/s
- Therefore,
[tex]\[
20 \text{ m/s} \times 3.6 = 72 \text{ km/hr}
\][/tex]
So, the car is moving at 72 km/hr.
The correct answer is:
- ○ 72 km/hr
