Question

A 6000 Kg rocket is set for vertical fring if the exhaust speed is $1000m{s}^1$ The amount of gas that must be ejected per second to supply the thrust needed to overcome the weight of the rocket is $(g=10m{s}^2)$

• A. 30 Kg/s
• B. 60 Kg/s
• C. 75 Kg/s
• D. 90 Kg/s

Answer 1

The correct option is B 60 Kg/s

Given that,

Mass $m=6000kg$

We know that,

The formula for thrust is that,

$F=u\times \frac{dm}{dt}$

Now, thrust = weight

$1000\times \frac{dm}{dt}=mg$

$1000\times \frac{dm}{dt}=6000\times 10$

$\frac{dm}{dt}=60kg/s$

Hence, the gas ejected per second is $60kg/s$