This preview shows page 1. Sign up to view the full content.
Problem 4.164 [Difficulty: 3] y x CS at speed U V e Y X Given: Data on rocket sled Find: Minimum fuel to get to 265 m/s Solution: Basic equation: Momentum flux in x direction Assumptions: 1) No resistance 2) p e = p atm 3) Uniform flow 4) Use relative velocities From continuity dM dt m rate = constant = so MM 0 m rate t ⋅ − = (Note: Software cannot render a dot!) Hence from momentum a rfx − M ⋅ dU dt − M 0 m rate t ⋅ − () ⋅ = u e ρ e V e ⋅ A e ⋅ ⋅ = V e − m rate ⋅ = Separating variables dU V e m rate ⋅ M 0 m rate t ⋅ − dt ⋅
This is the end of the preview. Sign up to access the rest of the document.