Problem 3.61 Challenge

พิจารณา F.B.D. ของวัตถุมวล m

a

v

\(R = bv^{2}\)

จาก \(ΣF_{x}= ma_{x}\)

\(-bv^{2} = m\frac{dv}{dt}\)

\(_{vt}\)

\(\int v^{-2}dv=-\frac{b}{m}\int dt\)

\(_{0}\)

\(_{u}\)

\(_{vt}\)

\(-\frac{1}{v}=-\frac{b}{m}t\)

\(_{u0}\)

\(-\frac{1}{u}\frac{1}{v}=-\frac{bt}{m}\)

\(\therefore v(t) =\frac{mu}{m + but}\;\blacksquare\)

จาก \(ΣF_{x}= 0\)

\(-bv_{T}^{2} = 0\)

\(v_{T}= 0 m/s \;\blacksquare\)