Explain how the end ball on the right of a Newton’s cradle moves when the end ball on the left was lifted and released.

Newton's Cradle works on the principle of Conservation of momentum

Explanation:

Newtons Cradle works on the principle of Conservation of Momentum, which states that when Collision happens between two or more bodies their Momenta remain conserved that is they remain same before and after collision.

m1*v1 = m2*v2

where m1 and m2 are the masses of the bodies and v1 and v2 are their velocity with which they are travelling.

Considering the case of Newton's Cradle, when a ball on the Left end is lifted to a height and then it is released so it imparts its momentum on the next ball, it seems that all the middle balls remain stationery but what actually happens is that their individual momenta are being transferred from on ball to the other.

Also when this momentum reaches to ball on the right there is no next ball therefore the ball on the rightmost position moves to nearly the same height as the one which was lifted on the left side.

One may note that whenever we lift one ball from any end, the same number of ball will be lifted from the other end. Like if we have lifted two balls from left end so two balls from the rightmost position will be lifted.  

need to see circuit to get time constant