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A rocket with a lift­off mass 3.5\times 10^{4}kg is blasted upwards with an initial acceleration of  10 m/s. Then the initial thrust of the blast is

  • Option 1)

    3.5\times 10^{5}N

  • Option 2)

    7.0\times 10^{5}N

  • Option 3)

    14.0\times 10^{5}N

  • Option 4)

    1.75\times 10^{5}N

 

Answers (1)

best_answer

As we learnt in

Rocket Propulsion -

\frac{dm}{dt}= rate\:of\;ejection\:of\:the\:fuel

\ast Thrust on the rocket

F=-\frac{udm}{dt}-mg

F= Thrust

\ast \:F=-\frac{udm}{dt}\:[\:if\:gravity\:neglected]

- wherein

Negative sign indicates direction of thrust is opposite to direction of gases

 

 

 

 

Initial thrust =( Lift - ­ off mass) \times acceleration

= \left ( 3.5\times 10^{4} \right )\times\left ( 10 \right )= 3.5\times 10^{5}N

Correct option is 1.

 


Option 1)

3.5\times 10^{5}N

This is the correct option.

Option 2)

7.0\times 10^{5}N

This is an incorrect option.

Option 3)

14.0\times 10^{5}N

This is an incorrect option.

Option 4)

1.75\times 10^{5}N

This is an incorrect option.

Posted by

divya.saini

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