[填空题]
Calculate the force exada* uywc.:zwv+m u/j0k+o; 1fjv6 zferted on a rocket, given that the propelling :xzdud t1 ;f ci3;h7nabvz-a 2bg mu81gases are expelledaz azvu3-;bfgxd;1mn bd 1u2h cti8:7 at a rate of $1500 \; kg/s$ with a speed of $ 4\times10^{4 } \; m/s$ (at the moment of takeoff). F = $\times 10^7 \; N$
