1. Write these down while you wait: 1 hr = 60 min = 3600 sec 1 km = 1000 m .6214 mile 1 mile = 5280 ft = 1760 yards  1609 m 1 m  3.281 ft 1 yard = 3 feet Shortcuts: 1 m/s = 3.6 km/hr  2.237 mph, (mph = miles/hour) 1 mph  1.47 f/s (1.46666666…) 1 f/s .682 mph (.6818181818…) Answer This Question: How many feet per second is 30 mph? (use any method you want – including help from others – but have an answer)

2. Write these down while you wait: 1 hr = 60 min = 3600 sec 1 km = 1000 m .6214 mile 1 mile = 5280 ft = 1760 yards  1609 m 1 m  3.281 ft 1 yard = 3 feet Shortcuts: 1 m/s = 3.6 km/hr  2.237 mph, (mph = miles/hour) 1 mph  1.47 f/s (1.46666666…) 1 f/s .682 mph (.6818181818…) Answer This Question: How many feet per second is 30 mph? (use any method you want – including help from others – but have an answer) (30 mph)(1.4666666) = 44 ft/s (30 mi)(5280 ft)(1 hr)= 44 ft/s ( hr )( 1 mi )(3600 s)

3. Dimensional Analysis Contents: Handy things to know Ways to convert Whiteboard practice

5. Ways to convert units: 1.Unit cancellation 2.Calculator’s built in (TI 85/86) 3.Conversion factors 4.Google Unit cancellation: 30. mph to ft/s: 30. mi(5280 ft)( 1 hr ) hr ( 1 mi )(3600 s) = 44 f/s (note the units canceling) Conversion factor: 30. mph to ft/s: (1 mph = 1.47 f/s) 30. mph x (1.47) = 44.1 = 44 ft/s (slightly off - what’s the “real” conversion factor?) Google: Type 30. mph in ft/s into the search bar (text it to 466453?) Calculator (TI 85/86) 2 nd CONV, MORE, MORE, SPEED, 30 mi/hr > ft/s

6. Whiteboards: Conversions 11 | 2 | 3 | 4 | 52345 TOC

7. Convert 32 mile/hour to feet/second 5280 ft = 1 mi 3600 s = 1 hr 32 mi(5280 ft)( 1 hr ) = 46.933333 hr ( 1 mi )(3600 s) 47 f/s (2 sig figs) 47 f/s W

8. Convert 88.0 feet/second to mph 5280 ft = 1 mi 3600 s = 1 hr 88 ft( 1 mi )(3600 s) = 60 mph s (5280 ft)( 1 hr ) 60.0 mph W

9. Convert 27.2 m/s to km/hr 1000 m = 1 km 3600 s = 1 hr 27.2 m ( 1 km )(3600 s) = 97.92 km/hr s (1000 m)( 1 hr ) 97.9 km/hr W

10. Convert 110. km/hr to m/s 1000 m = 1 km 3600 s = 1 hr 110 km (1000 m)( 1 hr ) = 30.55556 m/s hr ( 1 km )(3600 s) 30.6 m/s W

11. Convert 110. km/hr to mph 1 km .6214 mile 3600 s = 1 hr ?? 110 km (.6214 mi) = 68.354 mph hr ( 1 km ) 68.4 mph W

12. A car traveling 80. km/hr will go how far (in meters) in 2.7 seconds? 1000 m = 1 km 3600 s = 1 hour (60x60) (km/hr)/(3.6) = m/s 80. km/hr(1000m/km)(3600s/h) = 22.22 m/s v = x/t 22.22 m/s = x/( 2.7 s) x = ( 22.22 m/s)(2.7 s) = 60 m= 60. m 60. m W

13. A car goes 132 feet in 3.1 seconds. What is its speed in miles per hour? v = x/t v = (132 f)/(3.1 s) = 42.5806 f/s 42.5806 f/s(3600 s/h)/(5280 f/mi) = 29 mph 170 f W

14. A Baseball going 75 mph takes how much time to go 90. feet? 1 mile = 5280 feet 3600 s = 1 hour (60x60) 1 mph = 1.47 f/s (1.466666... f/s) 75 mi/hr(5280 ft/1 mi)(1 hr/3600 s) = 110 f/s v = x/t 110 f/s = ( 90. f)/t t = (90. f)/(110 f/s) =.818181818 s =.82 s.82 s W