How Far Does the Car Travel to Overtake the Truck?

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Homework Help Overview

The problem involves a car accelerating from rest at an intersection and a truck traveling at a constant speed. The objective is to determine the distance the car travels to overtake the truck after both start moving at the same time.

Discussion Character

  • Exploratory, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants discuss the need for equations of motion for both vehicles and the relationship between their positions over time. Some express confusion about how to start the problem and the relevance of time in their calculations.

Discussion Status

Some participants have provided initial thoughts on the equations to use, while others are seeking clarification on how to relate the positions of the car and truck as they move. There is an ongoing exploration of the necessary variables and equations needed to approach the problem.

Contextual Notes

Participants note the initial conditions, such as the car starting from rest and the truck's constant speed. There is also mention of the need to identify known and unknown variables to progress in the discussion.

The1
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Homework Statement


At the instant the traffic light turns green, a car that has been waiting at an intersection starts ahead with a constant acceleration of 2.80 m/s^2. At the same instant a truck, traveling with a constant speed of 17.0 m/s, overtakes and passes the car.

How far beyond its starting point does the car overtake the truck?

Homework Equations


One of the four constant acceleration equations


The Attempt at a Solution


I honestly have no idea how to start this, but I think I need a graph to solve.
 
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You do not need a graph to solve this problem, but a picture always helps.

In order to get help on this forum you need to show some work.

Can you list the variables you know and don't know?
Can you give me the equations of motion for one or both of the vehicles?

Give me something so I can know what is confusing you.
 
Well, I'm a bit lost on this question but here goes.

Car:
I think I use the equation X = 1/2*a*t[tex]^{2}[/tex] because X initial and V initial are 0.Of course I don't know how helpful this is as I don't have the time.

Truck:
All I know is the constant velocity is 17 m/s. The truck overtakes the car at X=0

The intersection is X=0 and t=0.

I need to know the distance it takes the car to overpass the truck, and at what velocity.

Again, I'm not to sure of the accuracy of this post
 
your post is accurate,
now, what is the equation of the coordinate X1 of the truck in fuction of time ?

now the truck intersects the car at t=0 X=0, that's true, but we need the second intersection time and distance.

let X(t) the coordinate of the car, let X1(t) the coordinate of the trucks,
what's the relation between X(t) and X1(t) when the car and truck intersect again ?
 
The1 said:
Well, I'm a bit lost on this question but here goes.

Car:
I think I use the equation X = 1/2*a*t[tex]^{2}[/tex] because X initial and V initial are 0.Of course I don't know how helpful this is as I don't have the time.

Truck:
All I know is the constant velocity is 17 m/s. The truck overtakes the car at X=0

The intersection is X=0 and t=0.

I need to know the distance it takes the car to overpass the truck, and at what velocity.

Again, I'm not to sure of the accuracy of this post

As tabchouri said, this sounds good. Now, what do we know about the x coordinates of both vehicles when they intersect?
 

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