Final Velocity Calculation for Inelastic Collision of Freight Trains

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In a completely inelastic collision between two freight trains, the final velocity must be calculated using the conservation of momentum. The masses of Engine 1 and Engine 2 are 1.4x10^4 kg and 1.5x10^4 kg, respectively, with initial velocities of 45 km/h [N] and 53 km/h [W]. The user initially miscalculated the momentum by not dividing by the total mass after summing the momentum contributions. The correct final velocity, as per the textbook, is 9.7 m/s. Acknowledging the mistake in the calculation process is crucial for arriving at the correct answer.
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Homework Statement


Two freight trains have a completely inelastic collision at a track crossing. Engine 1 has a mass of 1.4x10^4 kg and is initially traveling at 45 km/h [N].
Engine 2 has a mass of 1.5x10^4 kg and is initially traveling at 53 km/h [W]. Calculate the final velocity.

Homework Equations

The Attempt at a Solution


p^2=p1^2+ p2^2
=(1.4x10^4)(12.5m/s)^2+ (1.5x10^4)(14.72m/s)^2
=281740m/s

The answer in the textbook is 9.7m/s. What am I doing wrong?
 
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I just realized my mistake, i forgot to divide it by both mass
 

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