Laws Of Motion Question 50
Question: At a certain instant of time the mass of a rocket going up vertically is 100 kg. If it is ejecting 5 kg of gas per second at a speed of 400 m/s, the acceleration of the rocket would be (taking $ g=10m/s^{2}) $ [NCERT 1984]
Options:
A) $ 20m/s^{2} $
B) $ 10m/s^{2} $
C) $ 2m/s^{2} $
D) $ 1m/s^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
The acceleration of a rocket is given by $ a=\frac{v}{m}( \frac{\Delta m}{\Delta t} )-g=\frac{400}{100}( \frac{5}{1} )-10 $
$ =(20-10)=10m/s^{2} $
