Covert 90 m/s into miles/hr. (1 mile = 1.609 km)
A. 402 miles/hr
B. 90 miles/hr
C. 201.37 miles/hr
D. None of these
E. 301.3 miles/hr
The correct answer and explanation is:
To convert 90 meters per second (m/s) into miles per hour (mph), we use unit conversion factors step-by-step.
Step-by-Step Conversion:
1. Convert meters to kilometers:
90 m/s=901000=0.09 km/s90 \, \text{m/s} = \frac{90}{1000} = 0.09 \, \text{km/s}
2. Convert seconds to hours:
There are 3600 seconds in an hour, so:
0.09 km/s×3600 s/hr=324 km/hr0.09 \, \text{km/s} \times 3600 \, \text{s/hr} = 324 \, \text{km/hr}
3. Convert kilometers to miles:
Using the conversion:
1 mile=1.609 km⇒1 km=11.609 miles1 \, \text{mile} = 1.609 \, \text{km} \Rightarrow 1 \, \text{km} = \frac{1}{1.609} \, \text{miles}
So, 324 km/hr×1 mile1.609 km=201.37 miles/hr324 \, \text{km/hr} \times \frac{1 \, \text{mile}}{1.609 \, \text{km}} = 201.37 \, \text{miles/hr}
✅ Correct Answer: C. 201.37 miles/hr
💡 Explanation (300 words):
To convert speed from meters per second (m/s) to miles per hour (mph), it is essential to follow systematic unit conversions. First, we know that 1000 meters make 1 kilometer, and 3600 seconds make 1 hour. So, to go from meters/second to kilometers/hour, we multiply by 3.6: 90 m/s×36001000=324 km/hr90 \, \text{m/s} \times \frac{3600}{1000} = 324 \, \text{km/hr}
Next, to convert kilometers to miles, we use the known conversion that 1 mile = 1.609 kilometers, or conversely, 1 kilometer = 1 ÷ 1.609 = 0.621371 miles. Therefore: 324 km/hr×0.621371=201.37 miles/hr324 \, \text{km/hr} \times 0.621371 = 201.37 \, \text{miles/hr}
This final value tells us how fast 90 m/s is in terms of miles per hour. The correct result is approximately 201.37 mph, which matches option C.
This conversion is crucial in scientific, engineering, and international contexts where different measurement systems (SI vs. Imperial) are used. Whether calculating vehicle speeds or converting units for physics problems, being fluent with these conversion steps ensures accuracy and clarity.