A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 m/s. To give an initial upward acceleration of 20m / s2, the amount of gas ejected per second to supply the needed thrust will be (g = 10m/s2)

Given, mass of rocket m = 5000 k8, exhaust speed u =800 m / s, acceleration of rocket a =20m/s2 and g =10m/s2Upward force F =T -Wor Ma=T-Mg∴ T=M[a+g]=5000[20+10]=15×104NAlso, T=udMdt  or  dMdt=Tu∴ dMdt=15×104800=187⋅5kg/s