# Physics

posted by .

A blue car moving at constant speed of 10m/s passes a polic car that is at rest. The police car accelerates from rest at 4m/s^2 for 3.0 seconds and then maintains a constant speed. The blue car maintains constant speed for the entire 12 seconds. When does the police car pass the blue car?

Calculations:
Blue Car:
Vi= 10 m/s
Vf = 10 m/s
deltaT = 12 s
acceleration = 0

Police Car:
Vi = 0m/s
acceleration = 4m/s^2 (for the first 3 seconds)
deltaD (for first three seconds) = 18 m
Vf = 12 m/s

So when the deltaD of the blue car = the deltaD of the police car, the police car is at the same distance as the blue car.

How would I go about doing this?

• Physics -

A blue car moving at constant speed of 10m/s passes a polic car that is at rest. The police car accelerates from rest at 4m/s^2 for 3.0 seconds and then maintains a constant speed. The blue car maintains constant speed for the entire 12 seconds. When does the police car pass the blue car?

The police car accelerates at 4m/s^2 for 3 seconds reaching a final speed of 12m/s^2 and traveling a distance of at^2/2 = 4(3^2)/2 = 18m.

At this 3 second point, the blue car has traveled 3(10) = 30m.

From this point on, the police car will close the existing gap of 12m between the cars at a closing speed of 12 - 10 = 2m/s.

Thus, the police car will overtake, and pass the blue car in 12/2 = 6 seconds or 9 seconds after the blue car started.

• Physics -

ME NO MO

## 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 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, …
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 police car is at rest beside a road, looking for speeders. A car passes going at a constant speed of 30.0 m/s. The police car starts up 4 seconds later and accelerates at 2 m/s sq. until it reaches a speed of 40m. If the police car …
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 12

A sports car is travelling along a highway at a constant velocity of 36 m/s [N] exceeding the speed limit. It passes an unmarked police car parked on the shoulder of the highway. The police car accelerates from rest, 3.0 s after the …
9. ### 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 …
10. ### 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, …

More Similar Questions