Laws Of Motion Question 280
Question: A 600 kg rocket is set for a vertical firing. If the exhaust speed is $ 1000m{{s}^{-1}} $ , the mass of the gas ejected per second to supply the thrust needed to overcome the weight of rocket is
Options:
A) $ [117.6\text{ kg}{{\text{s}}^{-1}}] $
B) $[58.6\text{ kg}{{\text{s}}^{-1}}] $
C) $ [6\text{ kg}{{\text{s}}^{-1}}] $
D) $ [76.4\text{ kg}{{\text{s}}^{-1}}] $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ \text{Thrust }=\frac{udM}{dt}=mg $
$ \Rightarrow \frac{dM}{dt}=\frac{mg}{u}=\frac{600\times 10}{1000}=6\text{ kg}{{s}^{-1}} $
