A Herculean bomber jet accepts 40kg of air per second at a velocity of 200m/s, burns 2kg of fuel at the same time,and releases exhaust gases at 600m/s relative to the bomber. find the thrust due to its engine.
thrust = rate of change of momentum
mass per second in = 40
momentum per second in = 8000
mass per second out = 42
momentum per second out =42*600 = 25200
change of momentum per second = 17200 kg m/s^2
which is
17200 Newtons
By the way, that is Newton #2
which you know better as
F = m A
but
that assumes m is constant
really originally Newton said
F = d/dt (m V)
which for constant m is
F = m dV/dt
but dV/dt = A
so for constant m
F = m A