Momentum September 21, 2010

Momentum Linear Angular In all cases, momentum is CONSERVED. A vector that depends on two physical quantities: the mass and the velocity of the moving object Angular The momentum of a rotating object (not covering this yet) In all cases, momentum is CONSERVED. FORMULA: p = mΔv

Conservation of Momentum the total momentum of a closed system of objects is CONSTANT pi = pf mΔvi = mΔvf If there are 2 objects… m1Δvi1 + m2Δvi2 = m1Δvf1 + m2Δvf2 In collisions, we will have to break down momentum into x & y dimensions pix = pfx piy = pfy

Impulse An impulse is a force given to an object over a change in time. This impulse changes the objects momentum. Momentum (our next unit) is found by multiplying an object’s mass by its velocity Impulse = the variable “J” J = Ft = mv We need to include impulses in our F equations

Conservation of Energy In all processes, energy is conserved Ei = Ef We are going to look at 2 types of energy Kinetic= the energy of motion= ½ mv2 Can an object have kinetic energy if it is at rest? Potential = the energy of position = mgh =(mass)(10m/s2)(height) If something is at ground level, will it have potential energy? KEi + PEi = KEf + PEf ½ mvi2 + mghi = ½ mvf2 +mghf