Conversion of Speed, Time and Distance

To convert from \(\mathrm{km} /\) hour to \(\mathrm{m} / \mathrm{sec}\), we multiply by \(5 / 18\). So, \(1 \mathrm{~km} /\) hour \(=5 / 18\) \(\mathrm{m} / \mathrm{sec}\)
To convert from \(\mathrm{m} / \mathrm{sec}\) to \(\mathrm{km} /\) hour, we multiply by \(18 / 5\). So, \(1 \mathrm{~m} / \mathrm{sec}=18 / 5\) \(\mathrm{km} /\) hour \(=3.6 \mathrm{~km} /\) hour
Similarly, \(1 \mathrm{~km} / \mathrm{hr}=5 / 8\) miles \(/\) hour
1 yard \(=3\) feet
1 kilometer \(=1000\) meters \(=0.6214\) mile
1 mile \(=1.609\) kilometer
1 hour \(=60\) minutes \(=60 \times 60\) seconds \(=3600\) seconds
1 mile \(=1760\) yards
1 yard \(=3\) feet
1 mile \(=5280\) feet
\(1 \mathrm{mph}=(1 \times 1760) /(1 \times 3600)=22 / 45\) yards \(/ \mathrm{sec}\)
\(1 \mathrm{mph}=(1 \times 5280) /(1 \times 3600)=22 / 15\) ft \( / \mathrm{sec}\)
For a certain distance, if the ratio of speeds is \(a: b\), then the ratio of times taken to cover the distance would be \(b: a\) and vice versa.