[填空题]
Calculate the force exerted on a o+lci0o6w)cyp)l :fbrocket, given that the propelling gases are ex 9qb6bkcl cpg:vn 41fs4+(mappelled at a ra+nlqfcb c( 4p4 91asp6 bmvgk:te of $1500 \; kg/s$ with a speed of $ 4\times10^{4 } \; m/s$ (at the moment of takeoff). F = $\times 10^7 \; N$
