Mechanics · Momentum
Chapter 1 · 3
The idea
Coefficient of restitution and direct collisions
The second equation every collision needs: Newton's law of restitution, speed of separation = e × speed of approach. With it you can say where two spheres go after a direct impact, which values of e reverse a direction, how much kinetic energy is lost, what impulse each sphere receives, how a sphere rebounds from a fixed wall, and whether the spheres will collide again.
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Mechanics · Momentum
Coefficient of restitution and direct collisions
The second equation every collision needs: Newton's law of restitution, speed of separation = e × speed of approach. With it you can say where two spheres go after a direct impact, which values of e reverse a direction, how much kinetic energy is lost, what impulse each sphere receives, how a sphere rebounds from a fixed wall, and whether the spheres will collide again.
Why it works
One equation, two unknowns
Two small smooth balls of equal radius move towards each other along a straight line on a smooth table: , of mass kg, at and , of mass kg, at . They collide head-on. Where does each ball go?Call the velocities after the impact and , both measured in the positive direction. Conservation of momentum gives , which isKeep reading — free
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