Question

Convert the speed of light, 3.0 × 10^8 m/sec, into mi/hr

Answer 1

[Hint: 1 m/s=2.237 mi/hr] Write it out to get an understanding of how to convert. 1} 3.0x10^8m/s over 1. (Don't forget to put your units as stated above) 2} Utilizing the hint given you want to cancel out the unit that is being converted. (Ex: m/s) -> 3.0x10^8 m/s over 1 TIMES 2.237 mi/hr over 1 m/s Now notice that the m/s is on top and on bottom now, if you've written it out. The numerator has something in common with the denominator and can now be canceled out. (Cross out the m/s NOT the digits JUST the units) 3} You have now narrowed it down to digits and the desired unit you want. -> 3.0x10^8 over 1 TIMES 2.237 mi/hr over 1 Remember: multiply the numbers straight across the numerator to get a new total for the numerator. The same will go for the denominator. Once you have 1 fraction left, it basically becomes a math equation. Num ■(3.0×10^8)(2.237)= 671100000 Den ■ (1)(1)= 1 4} 671100000(mi/hr)/1= 671100000 mi/hr If you thought you were done you're wrong. You have to consider the significant figures or sig figs. Learn the rules to sig figs and you'll ace this part. You're answer is going to be 3 sig figs. Therefore, your answer is: 6.71x10^8 mi/hr