Print Info Two rather unequal cars are competing in a drag race. For simplicity,

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Print Info Two rather unequal cars are competing in a drag race. For simplicity, let's assume that the accelerations of the cars are constant. Car 1 has an acceleration of 3.9 m/s2, while Car 2 has an acceleration of 5.9 m/s2. Car 2 gets off to a late start, 0.9 seconds after Car 1 At what time after Car 1 took off will it be overtaken by Car 2? (in s) A: 3.3B: 3.8 C: 4.3 D: 4.8E: 5.4 Submit AnswerTres 0/1 How far down the track will this happen? (in m) A: 36 OB: 45 C: 56 D: 71 E: 88 Submit Answer Tries 0/1 How much faster will Car 2 be than Car 1 by that time? (in m/s) C: 2.1D: 3.0 : 4.3 A: 0.980 B: 1.4 Submit Answer Tries 0/1 Lgeneraiereferences on what is marked as New ger new logical View Other Views

Explanation / Answer

For car 1, d = ½ * 3.9 * t^2

Since car 2 starts 0.9 seconds after car1, let t – 0.9 be the time for car 2.
For car 2, d = ½ * 5.9 * (t – 0.9)^2
(t – 0.9)^2 = t^2 – 1.8 * t + 0.81
½ * 5.9 * (t – 0.9)^2 = 2.95 * t^2 – 5.31 * t + 2.39

Set these two distances equal to each other and solve for t.
t 4.8 seconds

For car 1, d = ½ * 3.9 * 4.8^2 45 m  

For car 1, vf = 3.9 * 4.8 = 18.72
For car 2, vf = 5.9 * 3.9 = 23.01
23.01 – 18.72 = 4.3 m/s

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