Laws Of Motion Question 434
Question: A rocket of initial mass 6000 kg ejects mass at a constant rate of 20 kg/s with constant relative speed of 10 km/s. What is the acceleration of the rocket after 50 second, (Neglect gravity)
Options:
A) $ 50m/s^{2} $
B) $ 40m/s^{2} $
C) $ 60m/s^{2} $
D) 30 m/$ \Omega $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Mass of the rocket after 50 seconds is: $ m=m _{0}-\mu t $
Here $ \mu =20kg/s $
$ =(6000)-(20)(50)=5000kg $
Thrust force$ F={V _{rel\mu }} $
$ \therefore $ $ F=(10\times 10^{3}m/s)(20kg/s) $
$ =2.0\times 10^{5}N $
$ \therefore $ Acceleration $ a=F/m=\frac{2\times 10^{5}}{5000}=40m/s^{2} $
