* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Lecture15 - Purdue Physics
Survey
Document related concepts
Work (physics) wikipedia , lookup
Rigid body dynamics wikipedia , lookup
Centripetal force wikipedia , lookup
Hamiltonian mechanics wikipedia , lookup
Equations of motion wikipedia , lookup
Relativistic quantum mechanics wikipedia , lookup
Old quantum theory wikipedia , lookup
Tensor operator wikipedia , lookup
Uncertainty principle wikipedia , lookup
Symmetry in quantum mechanics wikipedia , lookup
Classical central-force problem wikipedia , lookup
Quantum vacuum thruster wikipedia , lookup
Laplace–Runge–Lenz vector wikipedia , lookup
Transcript
READING QUIZ When cue ball collides with another billiard ball initially at rest, 1. "the total momentum of the two balls is the same as it was before." 2. "each ball has the same momentum after the collision as it did before." 3. "each ball has the same kinetic energy after the collision as it did before." Momentum is a vector: Magnitude = mass times speed = mv Direction = same as velocity (To be more precise, this is the linear momentum.) Momentum is important because it can be conserved, just like mechanical energy. Since Momentum is a VECTOR, Each componet of momentum is individually conserved! Px and Py and Pz We also want to know about changes in momentum. Notation: initial momentum pi final momentum change in momentum pf Dp = pf - pi Change in momentum is the result of a force! We can rearrange F = ma to be F=m Dv/Dt = Dp/Dt Dp = FDt Or, Change in momentum = Impulse. Fig. 7.2 Fig. 7.6 Is momentum conserved? If the net external force acting on a system of objects is zero, the total momentum of the system is conserved. Fig. 7.10 What makes a rocket move? Lecture Quiz - Question 1: Which ball experiences a greater force? A. Elastic B. Perfectly inelastic.