Newton's Cradle and Collisions

Also called

newton's cradle · newtons cradle · collisions · elastic collision · inelastic collision · perfectly inelastic collision · conservation of momentum · conservation of kinetic energy · coefficient of restitution · bouncing ball · clay balls stick · one in one out · two in two out · kinetic energy lost as heat · one dimensional collision · टक्कर · प्रत्यास्थ टक्कर · संवेग संरक्षण

Topics

• In every collision between two bodies the total momentum just before equals the total momentum just after.
• In an elastic collision the total kinetic energy is also conserved; in an inelastic one some becomes heat and sound.
• Equal steel balls colliding elastically swap velocities: one ball in sends one ball out at the same speed.
• Two balls swung in send two out: this is the only outcome that conserves both momentum and kinetic energy.
• When a clay ball sticks to a resting clay ball of equal mass, the pair moves on at half the speed.
• Sticking halves the momentum of each ball but the total is unchanged; half the kinetic energy becomes heat.
• Kinetic energy is ½mv²: two balls at half speed carry only a quarter each, so half the energy is gone.
• The coefficient of restitution e is the speed of separation divided by the speed of approach; e = 1 is elastic.
• A ball dropped from height h bounces to e²h: with e = 0.7 each peak is about half the one before; clay has e ≈ 0.

About this model

A GLB file of about 205 KB, shown in Lably's 3D viewer and, on a phone, placed in your room with AR. Credit: Model, science and animation: Lably (built procedurally with three.js; no downloaded meshes). | CC BY 4.0. Original geometry and animation made for Lably.

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