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physics qs help please?

A rocket, initially at rest on the ground, accelerates straight upward from rest with constant acceleration 49.0m/s2 . The acceleration period lasts for time 8.00s until the fuel is exhausted. After that, the rocket is in free fall.

Find the maximum height ymax reached by the rocket. Ignore air resistance and assume a constant acceleration due to gravity equal to 9.80 m/s2 .

2 Answers

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  • 7 years ago
    Favorite Answer

    u = 0 m/s, a = 49 m/s^2, t = 8 sec, v = ?

    Using 1st equation of motion,

    v = u + at

    v = 0 + 49 x 8 = 392 m/s

    Now you have to find distance (s)

    Using 3rd equation of motion,

    v^2 = u^2 + 2as

    (392)^2 = 0 + 2 x 49 x s

    153664 = 98s

    s = (153664)/(98) = 1568 m

    There is no need for acceleration due to gravity because you've asked to find only the distance.

  • 7 years ago

    find distance after 8secs

    using

    s = ut + 1/2at^2

    where s is the distance you want, u = 0, a = 49.0 and t = 8sec

    solve to get s = distance

    A complete solution has been posted here,

    http://cloudboard.us/questions/view.php?cat=Scienc...

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