A car travels at 72 kilometers per hour. What is this speed in meters per second? (1 km = 1000 m, 1 hour = 3600 seconds)

Convert kilometers to meters and hours to seconds: $72\ \text{km/h}=\frac{72\cdot1000\ \text{m}}{3600\ \text{s}}=\frac{72{,}000}{3600}=20$ m/s, choice H. A shortcut is that dividing km/h by $3.6$ gives m/s, and $72\div3.6=20$. Choice J ($259.2$) multiplies by $3.6$ instead of dividing, which is the conversion from m/s to km/h. Choice F ($0.02$) divides by $3600$ but forgets to multiply by $1000$. Choice G ($2.0$) is off by a factor of ten. Check by size: $20$ m/s for an hour is $72{,}000$ m, which is $72$ km.