Answer 41.7 years old
I answer this question already and it was correct!
Let say the two train cars are of masses
and 
now if the speed of two cars are
and 
then we can say that the momentum of two cars before they collide is given by

here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.
Now since in these two car motion there is no external force on them while they collide
So the momentum of two cars are always conserved.
hence we can say that the final momentum of two cars will be same after collision as it is before collision

Answer:
The answer is 1/16
Explanation:
1. Persistence of vision refers to the optical illusion that occurs when visual perception of an object does not cease for some time after the rays of light proceeding from it have ceased to enter the eye. 2. The persistence of vision for normal eye is 1/16 if a second.
It involves electrons.
The cathode is the electrode where electron deficient ions move to.
While the anode is electrode where electron excess ions move to.
So the relationship between Cathode and Anode involves electrons.
C.