Conversions II

1. Conversions II Converting derived units.

2. Conversion Factors • 1 kilo = 1000 (base unit) • 1 (base unit) = 1000 milli • 1 (base unit) = 100 centi • 1 year = 365 days • 1 day = 24 hrs • 1 hr = 60 min • 1 min = 60 sec

3. Revisit • Show all work! • No naked numbers! UNITS, UNITS, UNITS • Treat numbers as fractions • Multiply across • 3 sig figs

4. Problem: Convert 561 g into kilograms 1 kg 561 g 561 kg kg 5.61 E-1 kilo = 1000 or 103 = 103 1 g 103

5. Problem: Convert 90 s to hrs 1 90 s 1 hrs min 90 hrs = 60 1 s 60 min 60 x 60 2.50 E-2 hrs

6. Problem: Convert 45 km/hr to m/min 103 m 45 km 1 hr 45000 m = 1 60 min 1 hr km 60 min 7.50 E2 m/min Convert either km to m or hr to minutes first.

7. Problem: Convert 14 yrs to s 365 14 yrs 24 hrs 60 min 60 s days 1 1 yrs 1 day 1 hr 1 min 4.42 E8 s 4.42 E8 = s 1

8. Problem: Convert 14 km/hr to m/s 103 14 km 1 hr 1 min 14000 m m = 1 1 hr km 60 min 60 s 3600 s 3.89 m/s

9. Conversions – all into m/s. • 34 km/hr • 1200 cm/s • 3,000 km/hr • 67 km/day • 390,096 m/year