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perez asked in Science & MathematicsPhysics · 2 months ago

Physics help please?

A 1.8×104 kg rocket has a rocket motor that generates 2.9×105 N of thrust.

At an altitude of 5000 m the rocket's acceleration has increased to 7.1 m/s2 . What mass of fuel has it burned?

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  • 2 months ago

    There is a SERIOUS problem with insufficient significant figures in the question.  the thrust must be equal to (7.1+9.8)*m

    -> m = 2.9*10^5 /( 7.1+9.8)  {=1.72 +- 0.07 * 10^4} 

    take this away from 1.8 +- 0.05 * 10 ^ 4 and the answer is meaningless.

    the mass consumed must be between - 400 and + 2000 kg.

    From the figures provided it is possible that the rocket GAINED mass.

    To get a meaningful answer the accuracy would have had to be

    mass = 1.800 * 10 ^4  and the thrust 2.900 * 10 ^ 5  Only then would the answer have been meaningful.  ( 840 kg )

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  • 2 months ago

    1.8×104 kg ?? 2.9×105 N ??

    what do these mean?

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