EGR 280 Mechanics 11 – Newton’s Second Law

Newton’s Second Law Define the linear momentum of a particle as the product of its mass and velocity: L = mv Newton said: The resultant force acting on any particle is equal to the time rate of change of its linear momentum R = ∑F = d(mv)/dt = dm/dt v + m dv/dt If the mass of the particle is constant, then ∑F = m dv/dt = ma

Rectangular coordinates: ∑Fx = max ∑Fy = may ∑Fz = maz Intrinsic coordinates ∑Ft = mat = m dv/dt ∑Fn = man = m v2/ρ

The time derivative of the angular momentum is Define the angular momentum (or the moment of the momentum) of a particle about a point as H0 = r × mv H0 = r(mv)sinφ The time derivative of the angular momentum is y v φ m r x z