physics
posted by Nathan .
Two cars adjacent to each other on a highway. The first car accelerates uniformly at 3m/s2 the moment the light turns green. The second car is moving at 18m/s and is beside the first car at the instant the light changes and continues driving with a constant velocity. When are the cars side by side again?

Write equations for position from the light (X) vs time (t) and set them equal to each other.
Solve for t.
X1 = (a/2) t^2 = 1.5 t^2
X2 = 18 t
18t = 1.5 t^2
1.5 t (t  12) = 0
One answer is t=0. What is the other?
Respond to this Question
Similar Questions

Physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 4.8 m/s2 for 4.5 seconds. It then continues at a constant speed for 9.9 seconds, … 
Physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.5 m/s2 for 3.6 seconds. It then continues at a constant speed for 10.1 seconds, … 
physics
2 cars are in a race the first car is 200m ahead of the second car.the first car is moving with a uniform velocity of 30m/s while the second car starts from rest and accelerate to a rate of 4m/s how far and how long will it take the … 
physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 4.6 m/s2 for 4.4 seconds. It then continues at a constant speed for 8.5 seconds, … 
physics
Two cars are initially moving at constant speeds of 50 m/s (first car) and 30 m/s (second car) along a straight track with the first car being behind. At a certain point (e.g. point A) on the track the first car overtakes the other … 
physics with 6 questions
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.3 m/s2 for 3.9 seconds. It then continues at a constant speed for 13.7 seconds, … 
Physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 3.6 m/s2 for 4.5 seconds. It then continues at a constant speed for 7.3 seconds, … 
physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 5.5 m/s2 for 4.9 seconds. It then continues at a constant speed for 6.7 seconds, … 
physics
please somebdy help me solveing this. Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 4.3 m/s2 for 3.3 seconds. It then continues … 
Physics
Two cars start from rest at a red stop light. When the light turns green, both cars accelerate forward. The blue car accelerates uniformly at a rate of 5 m/s2 for 4.2 seconds. It then continues at a constant speed for 11.1 seconds, …