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The first & second stage of two stage rocket separately weigh 100 kg and 10 kg and contain 800kg and 90kg fuel respectively. If the exhaust velocity of gases is 2 km/sec then find velocity of rocket (nearly) (log_(10)5=0.6990) (neglect gravity) |
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Answer» Solution :`V=V_(0) + 2.3 log (m_(0)//m)` Velocity as the FIRST stage is detached `=V_(0)` `V_(0) = 2.3 ulog (m_(0)//m)` `=2.3 xx 2 xx 10^(3) xx log (1000//200)` `=2.3 xx 2 xx 0.699 xx 10^(3) = 3.2 xx 10^(3)` Velocity acquired with SECOND stage =V `V=V_(0) + 2.3 u log (m_(0)//m)` `=3.2 xx 10^(3) + 2.3 xx 2 xx 10^(3) xx log (100//10)` `=3.2 xx 10^(3) + 4.6 xx 10^(3) = 7.8 xx 10^(3) m//s` |
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