All Problems

Laws of Conservation

Problem 1.179

A rocket moves in the absence of external forces by ejecting a steady jet with velocity u constant relative to the rocket. Find the velocity \(\mathrm{v}\) of the rocket at the moment when its mass is equal to \(m,\) if at the initial moment it possessed the mass \(m_{0}\) and its velocity was equal to zero. Make use of the formula given in the foregoing problem.

Reveal Answer
v=uln(m0/m)\mathbf{v}=-\mathbf{u} \ln \left(m_{0} / m\right)