
Answer:
D(F)/ dt =  - 431  grs*m/s³
Step-by-step explanation:
F(t) Â = Â M(t)*a(t)
Taking derivatives on both sides of the equation we get
D(F)/ dt  =  DM(t)/dt * a(t)  + Da(t)/dt* M(t)    (1)
At time t = 10 s
M(t) = M(10) = 47 grs   and   DM(t)/dt = -6 grs/s
a(t)  =  a (10) = 17 m/s²  and    Da(t)/dt = -7 m/ s³
Plugging these values in equation (1) we get
D(F)/ dt  =  DM(t)/dt * a(t)  + Da(t)/dt* M(t)
D(F)/ dt = - 6 grs/s * 17 m/s²  + (-7) m/s³ *47 grs
D(F)/ dt =  -  102 grs*m/s³  - 329 grs*m/s³
D(F)/ dt =  - 431  grs*m/s³