* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Momentum
Analytical mechanics wikipedia , lookup
Lagrangian mechanics wikipedia , lookup
Fictitious force wikipedia , lookup
Newton's theorem of revolving orbits wikipedia , lookup
Monte Carlo methods for electron transport wikipedia , lookup
Brownian motion wikipedia , lookup
Hunting oscillation wikipedia , lookup
Hamiltonian mechanics wikipedia , lookup
Renormalization group wikipedia , lookup
Velocity-addition formula wikipedia , lookup
Routhian mechanics wikipedia , lookup
Relativistic quantum mechanics wikipedia , lookup
Symmetry in quantum mechanics wikipedia , lookup
Tensor operator wikipedia , lookup
Old quantum theory wikipedia , lookup
Centripetal force wikipedia , lookup
Matter wave wikipedia , lookup
Uncertainty principle wikipedia , lookup
Rigid body dynamics wikipedia , lookup
Classical mechanics wikipedia , lookup
Quantum vacuum thruster wikipedia , lookup
Work (physics) wikipedia , lookup
Laplace–Runge–Lenz vector wikipedia , lookup
Accretion disk wikipedia , lookup
Equations of motion wikipedia , lookup
Specific impulse wikipedia , lookup
Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup
Photon polarization wikipedia , lookup
Angular momentum wikipedia , lookup
Classical central-force problem wikipedia , lookup
Relativistic mechanics wikipedia , lookup
Angular momentum operator wikipedia , lookup
Chapter 6 Momentum Momentum and Collisions • This chapter is concerned with inertia and motion. • Momentum helps us understand collisions. • Momentum = mass X velocity • p = mv • Momemtum is a vector Sample Questions • Which has more momentum, a 1-ton car moving at 100 km/hr or a 2-ton truck moving at 50 km/hr? • Car • Truck p = mv = (1 ton)(100km/hr) p = (2 ton)(50 km/hr) • Large Momentum Examples: Huge ship moving at a small velocity P = mv High velocity bullet P = mv Impulse • Newton’s Second Law can read SF = ma = m(Dv/Dt) = (Dmv)/(Dt) = (Dp/ Dt) Rearranging, Impulse = Dp = FDt Sample Question • Does a moving object have impulse? Impulse is not a property of the object, but something that it can give or get from an interaction. Notice that it is not motion that gives us an impulse (v) but a change in motion (Dv). Sample Question • Does a moving object have momentum? Yes, but recall that motion is relative, so the momentum depends on having velocity with respect to the standard of rest. When Force is Limited • Apply a force for a long time. Examples: Follow through on a golf swing. Pushing a car. F Dt Make it Bounce p1 p2 = -p1 Dp = p2 - p1 = -p1 - p1 = -2p1 Minimize the Force • To minimize force … Increase Dt catching a ball Bungee jumping Dt F Maximize Momentum Change Apply a force for a short time. Examples: Boxing Karate F Dt • If SF = 0, then impulse = Dp = zero, or Momentum is conserved Demonstrations • Rocket balloon • Cannon • Rocket Scooter When can Momentum be Conserved? Internal forces cannot cause a change in momentum of the system. For conservation of momentum, the external forces must be zero. COLLISIONS • Collisions involve forces internal to colliding bodies. • Inelastic collisions - conserve momentum • Totally inelastic collisions - conserve momentum and objects stick together • Elastic collisions - conserve energy and momentum v = 10 v=0 M M v’ = 5 M Mv = 2Mv’ v’ = ½ v M Before Collision p = Mv v’ After Collision p = 2Mv’ Collisions Air Track Link Conserve Energy and Momentum Before Collision Case 1: Equal masses Case 2: M>M Case 3: M<M