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Laws of Motion

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Question : 9 of 40
Marks: +1, -0
A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m s−2^{-2}. Calculate the initial thrust (force) of the blast.
Solution:  
Here, M = 20,000 kg;
Initial acceleration = 5 m s−2^{-2}
The rocket moves up against gravity.
Therefore, the blast has to produce a total acceleration given by
a=10+5=15 m s−2a = 10 + 5 = 15 \text{ m} \text{ s}^{-2}
Hence, the initial thrust of the blast,
F=maF = m a
=20,000×15= 20,000 \times 15
=3×105 N= 3 \times 10^{5} \text{ N}
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