Question

A rocket blasts off from rest and attains a speed of 45 m/s in 15 sec. An astronaut has a mass of 57 kg. What is the astronaut's apparent weight during takeoff?

Answer 1

As per the question,

Initial velocity of the rocket is (u)=0

Final velocity (v)=45 m/sec

time (t)=15 sec

Mass of the astronaut =57 Kg

Now, applying the newton's first law of motion,

Let the acceleration of the rocket is a,

$v=u+at$

$\Rightarrow 45=0+a\times 15$

$\Rightarrow a=\dfrac{45}{15}=3 m/sec^2$

Now,

During the take off of the rocket, pseudo force will work on astronaut.

Hence, $F=ma =57\times 3 =171N$

Hence total reading of the weighting machine =$mg+ma$

$=171+57\times 9.8 =729.6N$

Hence total reading of the weighting machine will be 729.6N.