How Do You Calculate When One Moving Object Overtakes Another?

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Homework Help Overview

The discussion revolves around a kinematics problem involving two moving objects: an automobile accelerating from rest and a truck moving at a constant speed. The objective is to determine when the automobile overtakes the truck and the distance at which this occurs.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate time and velocity but encounters difficulties. Some participants suggest using equations of motion to express the positions of both vehicles over time. There are questions about the meaning of the function x(t) and its role in the problem.

Discussion Status

Participants are exploring different ways to express the positions of the automobile and the truck. Some guidance has been offered regarding the equations to use, but there is no explicit consensus on the approach to take. The discussion is ongoing with various interpretations being considered.

Contextual Notes

The problem setup includes specific values for acceleration and initial positions, which may influence the discussion. There is an emphasis on understanding the relationship between the two vehicles' movements without providing a complete solution.

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kinematics question help please :)?

So I've tried to attempt this problem by finding possible things like time or velocity but it just does not come out right. Help is greatly appreciated :)

Problem:

At the instant the traffic light turns green, an automobile starts with a constant acceleration a of 2.0 m/s^2. At the same instant a truck is 13.4 m down the road and traveling with a constant speed of 9.3 m/s. (a) How far beyond the traffic signal will the automobile overtake the truck? (b) How fast will the automobile be traveling at that instant?

heres some work I did:
Truck:
v=x/t
9.3=13.4/t
t= 1.44 sThanks :)
 
Last edited:
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If you know how far are the truck and the car from the traffic light at any moment, this problem is easy to solve.

So, for the car you have

x(t)=\frac{1}{2}at^2.

And for the truck

x(t)=x_0+vt.

Now you just need to figure what is x_0 and what is the condition for the car and the truck to meet.
 


What is x(t)?
 


kittykatxox said:
What is x(t)?

x(t) is the function with t as a variable. It tells you what is the distance x from the traffic light at the time t.
 

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