# physics

posted by .

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, before applying the brakes such that the carâ€™s speed decreases uniformly coming to rest 247 meters from where it started. The yellow car accelerates uniformly for the entire distance, finally catching the blue car just as the blue car comes to a stop.
2)How fast is the blue car going 10.4 seconds after it starts?
3)How far does the blue car travel before its brakes are applied to slow down?
4)What is the acceleration of the blue car once the brakes are applied?

• physics -

1. V1 = Vo + at,
V1 = 0 + 4.6*4.4 = 20.24m/s.

2. V2 = V1 = 20.24m/s after 10.4s.

3. D = di + d2,
d1 = Vo*t + 0.5at^2,
d1 = 0 + 0.5*4.6*(4.4)^2 = 44.53m.

d2 = Vt = 20.24 * 8.5 = 172m.

D = 44.53 + 172 = 217m.

4. Ds = 247 - 217 = 30m = Stopping
distance.

a = (Vf^2 - Vo^2) / 2d,
a = (0 -(20.24)^2 / 60 = -6.83m/s^2.

## Similar Questions

1. ### 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, …
2. ### 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, …
3. ### physics

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 …
4. ### 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, …
5. ### physics

A tortoise and hare start from rest and have a race. As the race begins, both accelerate forward. The hare accelerates uniformly at a rate of 1.2 m/s2 for 4.3 seconds. It then continues at a constant speed for 11.7 seconds, before …
6. ### 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, …
7. ### 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, …
8. ### 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 …
9. ### 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, …
10. ### physics

A blue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.2 m/s2. A green car arrives at the position of the stop-light 7.5 s after the light had turned green. What is the slowest …

More Similar Questions