What Is the Initial Velocity of the Green Car with Constant Acceleration?

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Homework Help Overview

The problem involves two cars, a red car and a green car, moving toward each other with the red car having a constant velocity while the green car's initial velocity and acceleration are unknown. The positions where the cars pass each other are provided, and the goal is to determine the initial velocity of the green car under the assumption of constant acceleration.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss finding the time taken for the cars to meet and suggest equating the distance traveled equations for both cars. There is mention of using two equations of motion to solve for the two unknowns: the initial velocity and acceleration of the green car.

Discussion Status

The discussion is ongoing, with participants providing different approaches to tackle the problem. Some have offered potential calculations and methods, while others are welcoming new participants and encouraging further exploration of the problem.

Contextual Notes

There are two unknowns in the problem, which are the initial velocity and acceleration of the green car. The discussion reflects on the need to derive equations based on the provided positions and velocities of the cars.

cynical555
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Homework Statement


Two cars, a red one(left side) and a green one(right side), are moving toward each other in adjacent lanes. At time t=0, the red car is at position x= 0 m and the green car is at position x= 220 m. If the the red car has a constant velocity of 20km/hr, it passes the green car at x= 44.5 m. If the red car has a constant velocity of 40 km/hr, it passes the green car at x= 76.6 m. What is the initial velocity of the green car assuming its acceleration to be constant?

Homework Equations


The Attempt at a Solution


i found that the green car has moved 175.5 m after 8 s and that the car moved 143.4 m after 6.89s.
thanks in advanced!
 
Last edited:
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Now that you got the time, find the equation for the distance traveled for both cases and equate them together. Initial velocity and acceleration are the same for both of them, so you can find what you need. I got around ~51 m/s, ignoring sig figs. Hope that's correct.
 
two unknowns - initial velocity (u) and acceleration (a) of green car. you get two equations of motions, and two unknowns. so solve them to get the answer.
 
and Welcome to Physics Forums cynical555!
 

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