Atoy train of m=0.60 kg moves at 20m/s along a straight track. it bumps into another train of m=1.5kg moving in the same direction. they stick together and continue on the track at a speed 12 m/s. what was the speed in m/s of the second train just before the collision?

8.8 m/s

Explanation:

Given

mass of train

velocity of Train

mass of another train

Final velocity of both train

Let be the velocity of before collision

As external Force is zero therefore change in momentum is zero

conserving Momentum

the entire statement is true and correct.  

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firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.