Time & Velocity Homework: Police Car Overtake Speeder

In summary, the speeder passes the police car at 27.6 m/s while the police car is at rest. The police car then accelerates at a rate of 2.27 m/s^2 and catches up to the speeder after 24.32 seconds. The equation for the displacement of both cars with respect to time is x=1/2a(t)^2 + Vi(t).
  • #1
bigzee20
25
0

Homework Statement


A speeder passes a parked police car at a constant speed of 27.6 m/s. At the instant, the police car starts from rest with a uniform acceleration of 2.27 m/s^2. How much t passes before the speeder is overtaken by the police car.


I tried solving for t using t=Vf-Vi /a and i get 12.15sec, which is wrong what am i doing wrong?
 
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  • #2
bigzee20 said:

Homework Statement


A speeder passes a parked police car at a constant speed of 27.6 m/s. At the instant, the police car starts from rest with a uniform acceleration of 2.27 m/s^2. How much t passes before the speeder is overtaken by the police car.

I tried solving for t using t=Vf-Vi /a and i get 12.15sec, which is wrong what am i doing wrong?

Observe that to catch him they must both be at the same X at the same Time.

What is the equation for the PoPo's displacement with respect to time?
And for the reckless miscreant?

When they are equal, it's book'em Danno.
 
  • #3
OMMMMG I love u I GOT IT!
x=1/2a(t)^2 + Vi(t)

Cops= 1/2(2.27)(12.15)+0(12.15) = 13.79025
Speeder= 1/2(0)12.15+27.6(12.15) = 335.34
335.34/13.79025 = 24.32s
 
Last edited:
  • #4
bigzee20 said:
OMMMMG I love u I GOT IT!
x=1/2a(t)^2 + Vi(t)

Cops= 1/2(2.27)(12.15)+0(12.15) = 13.179025
Speeder= 1/2(0)12.15+27.6(12.15) = 335.34
335.34/13.179025 = 24.32s

??

I was thinking of something considerably more direct.

1/2*a*t2 = V * t

t = 2*V/a = 2*27.6/2.27 = 24.32 s
 

Related to Time & Velocity Homework: Police Car Overtake Speeder

1. What is the formula for calculating time and velocity in a police car overtaking a speeder?

The formula for calculating time and velocity is time = distance/velocity. This means that the time it takes for the police car to overtake the speeder is equal to the distance between them divided by the difference in their velocities.

2. How does the speed of the police car affect the time it takes to overtake the speeder?

The speed of the police car directly affects the time it takes to overtake the speeder. The faster the police car is traveling, the shorter the distance it needs to cover to catch up to the speeder, resulting in a shorter amount of time to overtake.

3. Can the relative velocity of the police car and the speeder affect the outcome of the overtake?

Yes, the relative velocity of the police car and the speeder can affect the outcome of the overtake. If the speeder is also increasing their speed, it may take longer for the police car to catch up to them, resulting in a longer time to overtake. On the other hand, if the speeder is decreasing their speed, it may take less time for the police car to overtake them.

4. Is it possible for the police car to overtake the speeder if they have the same velocity?

Yes, it is possible for the police car to overtake the speeder even if they have the same velocity. This can occur if the police car starts from a position ahead of the speeder or if the speeder slows down, allowing the police car to catch up and overtake them.

5. Are there any other factors that can affect the time and velocity of a police car overtaking a speeder?

Yes, there are other factors that can affect the time and velocity of a police car overtaking a speeder. These include the distance between the police car and the speeder, the acceleration of both vehicles, and any external factors such as road conditions or traffic. These factors can all impact the outcome of the overtake and should be taken into consideration when calculating time and velocity.

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