a) What are the physical principles that are important to understanding Newton\'

Question

a) What are the physical principles that are important to understanding Newton's cradle illustrated above?

b) Explain why these principles are applicable and use them to predict the behavior of the system if the balls one and two are retracted with the angle on the left and the ball five is retracted with the angle to the right and they are released at the same time to collide with bullets 3 and 4 that are at rest.

c) Comment on the long-term behavior of the system and why hard steel balls are used.

Explanation / Answer

When one releases 2 balls in Newton's cradle, two balls on the opposite side bounce out at approximately the same speed as the 1st pair, rather than one ball at higher speed, or 3 balls at lower speed. Newton's Cradle aptly demonstrates the principle of the conservation of momentum (mass times speed).
This principle states that when two objects collide, the total momentum of the objects before the collision is equal to the total momentum of the objects after the collision.In other words, when the first ball of Newton's Cradle collides with the second, the first ball stops, but its momentum isn't lost, just transferred to the second ball, then the third, then the fourth, until it reaches the very last ball.
For example, if only 1 ball came off with twice the velocity, momentum would be the same (conserved) as the incoming 2 balls, but there would be twice as much energy in the outgoing ball as there was in the 2 incoming balls. Conversely, if 4 balls came off with 1/2 the velocity, momentum would be conserved, but the energy would be half of what was put it in.

Why hardened steel balls?
Hardened steel balls is much more resistant to abrasion and wear than chrome steel. It is a high alloy, fine grain, through hardening, stainless steel. Because of its high hardness and fine grain structure, it can be finished to a fine dimensional quality.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.