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

AI Thread Summary
The discussion revolves around calculating the initial velocity of a green car with constant acceleration, given its interaction with a red car moving at two different constant speeds. The red car's positions at two speeds (20 km/hr and 40 km/hr) allow for the establishment of equations of motion for both cars. The green car's distance traveled was calculated to be 175.5 m after 8 seconds and 143.4 m after 6.89 seconds. By equating the distance equations for both scenarios, the initial velocity and acceleration of the green car can be determined. The estimated initial velocity of the green car is approximately 51 m/s, pending further verification.
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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