(a) Towns A and B in the figure below are 80.0 km apart. A couple arranges to dr
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Question
(a) Towns A and B in the figure below are 80.0 km apart. A couple arranges to drive from town A and meet a couple driving from town B at the lake, L. The two couples leave simultaneously and drive for 3.05 h in the directions shown. Car 1 (leaving from Town A) has a speed of 94.0 km/h. If the cars arrive simultaneously at the lake, what is the speed (in km/h) of car 2 (leaving from Town B)? 40.080.0 km 75.8 km/h (b) What If? If the couple departing from town B are delayed by a flat tire, how much later (in hours) can they leave town B after the first couple leaves town A and still reach the lake at the same time as the couple from town A? Assume that the speed limit on the road taken by the couple from town B is 88.5 km/h (55 mph) and that the couple obeys the speed limit. X hoursExplanation / Answer
distance between town A and lake r1 = v1*t = 94*3.05 = 286.7 km
distance between town B and lake , r2 = sqrt(286.7^2+80^2-(2*286.7*80*cos40))=231.2 km
speed of car 2 = v2 = r2/t = 231.2/3.05 = 75.8 km/h
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(b)
speed of car 2 , v2 = 85.5 km/h
time taken by car 2 to reach lake = t2 = r2/v2 = 231.2/85.5 = 2.70 h
couple B can leave after a time = 3.05 - 2.70 = 0.35 hours
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