If is given that B= Rate of burn of fuel mass

So can we right B=dm/dt or -dm/dt, which of these is accurate?

3 answers

if m is the mass of the rocket, the -dm/dt is more useful.
Here, m is the mass of the fuel remaining
Mass of system=massofrocket + massoffuel
dMassofSystem/dt=dm/dt and it is negataive. I assume the mass of the rocket does not change.