man i shouldve been paying more attention instead of doing maths, but i had tests to prepare for.. but i managed to get SMOEthing into my head.
we all know newton's second law, F = ma, now rockets move because there's a net force. that is, a netforce acting upwards, that's higher than gravity (something different to reaction force coz thats only enough to counter gravity, not push the rocket further)
the rocket burns fuel, it pushes it out, and as a result the fuel pushes the rocket upwards (newton's third law)
robson derrived the formula for momentum (p) from F = ma today, it goes like this
F = ma [where a = (v-u)/t]
F = m((v-u)/t)
F = (mv-mu)/t
Ft = mv - mu = /\p
see?
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