Answers to Chapter 1 Questions

1.1 Flying from Anne to Bev, the pigeon’s speed with respect to Earth is +30 ft/s. Flying from Bev to Anne, the wind reduces the pigeon’s speed to 10 ft/s, or a velocity of -10 ft/s.

1.2 Speed = Distance/Time so Time = Distance/Velocity. The distance is 100 feet and the speed going from Anne to Bev is 35 ft/s while the return speed is 5 ft/s. The total time is 100/35 + 100/5 = 22.9 seconds.

1.3 When the wind blows with a speed of 20 ft/s or more, the pigeon can never get back to Anne from Bev! The time becomes infinite.

1.4 250 feet

1.5 50 feet

1.6 V_PE = V_PB + V_BE. V_BE = 30 ft/s but V_PB = +50 ft/s going from Chuck to Dean and -50 ft/s going from Dean to Chuck. So V_PE = 80 ft/s going from Chuck to Dean.

1.7 V_PE = -20 ft/s going from Dean to Chuck.

1.8 V_XX = 0

1.9 Anne is at X_E = 0, Chuck is at X_E = 30 ft, the pigeon is at X_E = 50 ft, Dean is at X_E = 130 ft, and Bev is at X_E = 250 ft.

1.10 See diagram below:

Anne Chuck Bev Dean

1.11

Time	0 s	1 s	2 s	3 s	4 s	5 s
XEarth for Chuck	0 ft	30 ft	60 ft	90 ft	120 ft	150 ft
XEarth for Dean	100 ft	130 ft	160 ft	190 ft	220 ft	250 ft

1.12 X_E = 125 ft

1.13 X_B = -150 feet!