A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 m / s-1. To give an initial upward acceleration of 20 m / s -2, the amount of gas ejected per second to supply the needed thrust will be (Take g =10 m / s -2 )

Question

A 5000 kg rocket is set for vertical firing. The exhaust speed is 800 m / s-1. To give an initial upward acceleration of 20 m / s -2, the amount of gas ejected per second to supply the needed thrust will be (Take g =10 m / s -2 ) (A) 127.5 kgs -1 (B) 137.5 kgs -1 (C) 185.5 kgs -1 (D) 187.5 kgs -1

Tardigrade Admin · Accepted Answer

Given: Mass of rocket ( m )=5000 Kg Exhaust speed ( v )=800 m / s Acceleration of rocket (a)=20 m / s 2 Gravitational acceleration ( g )=10 m / s 2 We know that upward force F = m ( g + a )=5000(10+20) =5000 × 30=150000 N . We also know that amount of gas ejected ((d m/d t))=(F/V)=(150000/800) =187.5 kg / s

Q. A $5000 k g$ rocket is set for vertical firing. The exhaust speed is $800 m / s^{- 1}$ . To give an initial upward acceleration of $20 m / s^{- 2}$ , the amount of gas ejected per second to supply the needed thrust will be (Take $g = 10 m / s^{- 2}$ )

$127.5 k g s^{- 1}$

$137.5 k g s^{- 1}$

$185.5 k g s^{- 1}$

$187.5 k g s^{- 1}$

Q. A 5000kg rocket is set for vertical firing. The exhaust speed is 800m/s−1. To give an initial upward acceleration of 20m/s−2, the amount of gas ejected per second to supply the needed thrust will be (Take g=10m/s−2 )

127.5kgs−1

137.5kgs−1

185.5kgs−1

187.5kgs−1

Given : Mass of rocket (m)=5000Kg Exhaust speed (v)=800m/s Acceleration of rocket (a)=20m/s2 Gravitational acceleration (g)=10m/s2 We know that upward force F=m(g+a)=5000(10+20) =5000×30=150000N. We also know that amount of gas ejected (dtdm​)=VF​=800150000​ =187.5kg/s

Q. A $5000 k g$ rocket is set for vertical firing. The exhaust speed is $800 m / s^{- 1}$ . To give an initial upward acceleration of $20 m / s^{- 2}$ , the amount of gas ejected per second to supply the needed thrust will be (Take $g = 10 m / s^{- 2}$ )

$127.5 k g s^{- 1}$

$137.5 k g s^{- 1}$

$185.5 k g s^{- 1}$

$187.5 k g s^{- 1}$