A 0.25kg model rocket accelerates from 15 m/s to 40 m/s in 0.60 s.Calculate the force(s) exerted on the rocket

Answer 1

mass of model rocket 'm'=0.25 kg

acceleration 'a'=change in velocity /time=(40-15)/0.60=41.67 m/s^2

Rocket experiences two forces(1)gravity that is weight mg (2)engine(F)

As the two forces are in opposite direction,the resultant( F-mg)=ma

F -mg=ma gives F=mg+ma

If rocket is accelerating upwards,then force F=m(g+a)

F=0.25(9.8+41.67)=12.86 N

Answer 2

First, calculate acceleration and then the force

v(t)=15+a*t
since t=0.60
(40-15)/0.60=a
a=125/3 m/s^2

the force is
F=m*a
F=0.25*125.3
=31.3 N

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