I've already done 10 probs, but I can't figure these out. Please help if you can.
1. An automobile traveling v = 90 km/h overtakes a L = 1.00 km long train traveling in the same direction on a track parallel to the road. If the train's speed is 80 km/h, how long does it take the car to pass it, and how far will the car have traveled in this time?
What are the results if the car and train are traveling in opposite directions?
2. An unmarked police car traveling a constant 125 km/h is passed by a speeder traveling 140 km/h. Precisely 1.00 s after the speeder passes, the policeman steps on the accelerator. If the police car's acceleration is 2.50 m/s2, how much time passes after the speeder passes before the police car overtakes the speeder (assumed moving at constant speed)?
The Attempt at a Solution
1. dx=10t? Tried making it into a rel. vel. problem.
2. (38.9)^2=(34.7)^2+2(2.5)dx ?? I've been working on this one for an hour...