Car acceleration calculation problem

In summary: And for the car? Well, initially the car is 32 metres behind the train, travelling at a speed of 47+4vt. So we have for the car s=32+v_{train}t-32=0. So t=0 would give us the same value for s for both the train and the car.
  • #1
AraProdieur
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0

Homework Statement


A train is moving parallel and adjacent to a highway with a constant speed of 33 m/s. Initially a car is 32 m behind the train, traveling in the same direction as the train at 47 m/s and accelerating at 4 m/s^2.
What is the speed of the car just as it passes the train? Answer in units of m/s.



Homework Equations


So far, I have thought of using delta x= Vot+ 1/2at^2
I also think that I have to account for the displacement between the two trains, which is 14 m.
The thing that I don't understand is how to calculate something as it passes or catches up to another thing.

If there is any advice, thanks!
 
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  • #2
Let the point when the measurement starts be s=0, then you have all the initial conditions. Now consider the distance s as a function of time t, so [tex]s(0)=0[/tex] for the car and [tex]s(0)=32[/tex] for the train. Write two such formulae, one to describe each object. At the point where the car passes the train, the two distances are the same, so you can equate and get a time value [tex]t_{m}[/tex], where then you can calculate the speed of the car with the formulae describing uniform acceleration.
 
  • #3
bel said:
Let the point when the measurement starts be s=0, then you have all the initial conditions. Now consider the distance s as a function of time t, so [tex]s(0)=0[/tex] for the car and [tex]s(0)=32[/tex] for the train. Write two such formulae, one to describe each object. At the point where the car passes the train, the two distances are the same, so you can equate and get a time value [tex]t_{m}[/tex], where then you can calculate the speed of the car with the formulae describing uniform acceleration.

Yes, but I don't understand how to go about doing that. Like getting the two distances to equal the same? I did think of that as well, but didn't know how to use formulas to do something like that.
 
  • #4
Say, for the train, which is initially (i.e., at time [tex]t=0[/tex]) 32 metres ahead of the car, and travels with a constant velocity, say [tex]v_{train}[/tex]. Then we have for the train [tex]s=32+v_{train}t[/tex].
 

1. How is car acceleration calculated?

Car acceleration is calculated by dividing the change in velocity by the change in time. This can be represented by the equation a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

2. What factors affect a car's acceleration?

Several factors can affect a car's acceleration, including the car's weight, power and torque of the engine, aerodynamics, and traction of the tires. Additionally, external factors such as road conditions and weather can also have an impact on a car's acceleration.

3. How does a car's transmission affect its acceleration?

The type of transmission in a car can greatly impact its acceleration. A manual transmission allows the driver to control the gear shifts, providing more control over the car's acceleration. On the other hand, an automatic transmission shifts gears automatically, which may result in a smoother but less responsive acceleration.

4. Can car acceleration be improved?

Yes, car acceleration can be improved through various methods such as upgrading the engine, reducing the car's weight, and improving aerodynamics. Additionally, proper maintenance and tuning can also help improve a car's acceleration.

5. Why is knowing a car's acceleration important?

Knowing a car's acceleration is important for various reasons. It can help in understanding the car's performance and capabilities, which can be useful for racing or other high-speed activities. It can also aid in determining the car's fuel efficiency and overall efficiency. Additionally, having knowledge of a car's acceleration can also be crucial for safety reasons, such as when merging onto highways or passing other vehicles.

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