# Chapter02

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Unformatted text preview: This gives the elapsed time when they meet as t = 2.15 (a) v= (b) v = (c) v= 10.0 m − 0 = 5.00 m s 2.00 s − 0 ( 5.00 − 10.0) m ( 4.00 − 2 .00) s x(m) 10 8 6 4 2 0 –2 –4 –6 = − 2.50 m s ( 5.00 − 5.00) m = ( 5.00 − 4.00) s 0 25 1234567 8 t(s) CHAPTER (d) v = ( 8.00 − 7.00) s = 5.00 m s (a) A few typical values are t(s) 1.00 2.00 3.00 4.00 5.00 6.00 200 180 x(m) 5.75 16.0 35.3 68.0 119 192 160 140 x(m) 2.16 0 − ( − 5.00 m ) 2 120 100 80 60 40 20 (b) We will use a 0.400 s interval centered at t = 4.00 s . We find at t = 3.80 s , x = 60.2 m and at t = 4.20 s , x = 76.6 m . Therefore, ∆x 16.4 m v= = = 41.0 m s . ∆t 0.400 s 0 0.00 1.00 2.00 3.00 t(s) 4.00 5.00 6.00 Using a time interval of 0.200 s, we find the corresponding values to be: at t = 3.90 s , ∆x 8.20 m = = 41.0 m s . x = 64.0 m and at t = 4.10 s , x = 72 .2 m . Thus, v = ∆t 0.200 s For a time interval of 0.100 s, the values are: at t = 3.95 s , x = 66.0 m , and at ∆x 4.10 m = = 41.0 m s . t = 4.05 s , x = 70.1 m . Therefore, v = ∆t 0.100 s ∆x 68.0 m = = 17.0 m s . This 4.00 s ∆t value is m u ch le ss than the instantaneous velocity at t = 4.00 s . (c) At t = 4.00 s , x = 68.0 m . Thus, for the first 4.00 s, v = 2.17 (a) v 0.50 s = (b) v 2.0 s = (c) v 3.0 s = (d) v 4.5 s = x 1.0 s − x t = 0 1.0 s − 0 x 2.5 s − x 1.0 s 2 .5 s − 1.0 s x 4.0 s − x 2.5 s 4.0 s − 2 .5 s x 5.0 s − x 4.0 s 5.0 s − 4.0 s = = 4.0 m = 4.0 m s 1.0 s − 6.0 m = − 4.0 m s 1.5 s x(m) 4 3 2 1 –1 –2 = 0 =0 1.5 s = +2.0 m = 2.0 m s 1.0 s 26 1 2 3 4 5 t(s) CHAPTER 2.18 2 (a) The average speed during a time interval ∆t is v = d istan ce tr a v eled . ∆t During the first quarter mile segment, Secretariat’s average speed was 0.250 m i 1320 ft = = 52 .4 ft s 25 .2 s 25 .2 s v1 = ( 35.6 mi h ) . During the second quarter mile segment, v2 = 1320 ft = 55.0 ft s 24.0 s ( 37.4 mi h ) . For the third quarter mile of the race, v3 = 1320 ft = 55.5 ft s 23.8 s ( 37.7 mi h ) , and during the...
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## This note was uploaded on 03/03/2010 for the course PHY P221 taught by Professor Dr.ha during the Spring '05 term at Indiana University South Bend.

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