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Toranc3
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Homework Statement
The engineer of a passenger train traveling at 25.0 m/s sights a freight train whose caboose is 200 m ahead on the same track. The freight train is traveling at 15.0 m/s in the same direction as the passenger train. The engineer of the passenger train immediately applies the brakes, causing a constant acceleration of 0.100 m/s^2, while the freight train continues with constant speed. Take x=0 at the location of the front of the passenger train when the engineer applies the brakes.
Where will the collision take place?
Homework Equations
y=yo+vo*t+1/2*a*t^(2)
-b+- Sqrt(b^(2)-4ac)/2a
The Attempt at a Solution
yp-passanger train and yf=freight train
Yp=yo+vo*t+1/2*a*t^(2)
yp=25m/s*t - 0.05m/s^(2)*t^(2)
Yf=yo + vo*t +1/2*a*t^(2)
yf=200m +15m/s*t
yp=yf
-0.05m/s^(2)*t^(2) + 10m/s*t -200m
I get t= 177.4596 seconds and t=22.5403 seconds
How do I know which time is correct?