$1.$ A spacecraft in space executes a steady state impulsive burn with a single rocket engine to increase

its forward velocity. Before the burn, it has $87$ seconds of fuel on board $($which burns at a constant

rate$)$ and the ratio of its Propellant Mass Fraction to its Mass Ratio is $0\mathrm{.}68.$ After the burn, the

following measurements are reported:

$-$ Fuel Remaining in the spacecraft: $50\%$

$-$ Momentum Change of spacecraft: $680,720$ Ns

If the specific impulse of its engine is $270$ seconds, Find:

$2.$ Mass flow rate of the fuel