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Force & Momentum Force is the derivative of momentum as a function of time. F = ∆P/∆t = m∆v/∆t Of course ∆v/∆t is accel.
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Momentum & energy
Momentum P = mv Momentum is mass in motion Vector quantity Dimensions?
Force & Momentum Force is the derivative of momentum as
a function of time. F = ∆P/∆t = m∆v/∆t Of course ∆v/∆t is accel.
Momentum Conservation The momentum of a system is always
conserved. Complication - P is a vector qty. - which
means we will have vector considerations when working w/ P conservation.
Po = Pf Like relative velocity we have to create the
exact formula based on the specific circumstance.
Scenarios for P conservation Explosion Po = P1 + P2 +…. + Pn ; exact formula depends on # of pcs. before & after. Collisions --> Explosion P1o + P2o = P1f + P2f ; exact formula depends on # of pcs. before & after Collision --> Coalescence P1o + P2o = Pf ; typically here only 2 pcs. collide, see problem #13, p.238
Energy Exist in 7 forms - crimsen --> cr(h)msen Can be transferred - always involves
same form of energy. Can be transformed - involves more
than 1 form. Scalar quantity Energy is defined as the ability to do
work. Discuss implications.
Mechanical Energy 2 forms 1) kinetic, 2) potential Ek = 1/2mv2
Ep = mgh
Work W = Fd W = ∆Ek
W = ∆Ep
Work like E is a scalar quantity?? Fig. 10-2, p. 258
Energy Conservation The energy of a system is always conserved. Complication - 7 forms of energy & 2 forms of
mech. E. Elastic collision - mech. E conserved Inelastic collision - mech. E is not conserved. Falling body - Epo = Ekf
Exact form of E conservation eq. Is circumstance dependent.
P & E conservation Occurring to every system @ the same
time. Complicated b/c P is vector & E is
scalar & b/c energy exist in 7 forms.
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