d1 = 0.5a*t^2 = 0.5*2.4*3^2 = 10.8 m.
Head start for Jill.
0.5*4*t^2 = 0.5*2.4*t^2 + 10.8.
2t^2 = 1.2t^2 + 10.8.
0.8t^2 = 10.8
t^2 = 13.5.
t = 3.7 s. to catchup.
Jill and Traci are side by side in their cars at a red light. When the light changes, Jill takes off with an acceleration of 2.4m/sec^2. Traci waits 3 seconds and then takes off with an acceleration of 4m/sec^2. How long will it take her to catch Jill?
I've tried using the formula Vf=Vi+at to find their final velocities and I tried using the formula Vavg(t)=d to find their distances after 3 seconds but I can't seem to understand what formula I use to find the time it takes Traci to catch up with Jill or what to plug into that formula. I know the answer is 10.3 seconds from the answer sheet but I don't know how they got that answer. Thank you.
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