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    A spaceship of mass 5000kg is stationary in deep space. It fires its engine producing a forward thrust of 2000N for 2.5 mins, then turns them off. The spaceship then enters a cloud of interstellar dust which brings it to a halt after 7200km

    The spaceship travels in convoy with another spaceship the same in all respects, except that it carries another 500kg equipment.
    Both carry out the same procedure

    Which travels further into the dust cloud?

    The answer is the first spaceship by 655km, but I can't figure out how to get this answer

    Thankyou!
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    (Original post by Tasha_140)
    A spaceship of mass 5000kg is stationary in deep space. It fires its engine producing a forward thrust of 2000N for 2.5 mins, then turns them off. The spaceship then enters a cloud of interstellar dust which brings it to a halt after 7200km

    The spaceship travels in convoy with another spaceship the same in all respects, except that it carries another 500kg equipment.
    Both carry out the same procedure

    Which travels further into the dust cloud?

    The answer is the first spaceship by 655km, but I can't figure out how to get this answer

    Thankyou!

    Use F=ma to get a, then use suvat to get s, for the second spaceship and subtract from 7200.
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    okay, sorry, didn't read it properly; use f=ma for a for 1st spaceship, then suvat for dist, then work out stopping force to decelerate in 7200km, and use these values for total dist of 2nd spaceship
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    force multiplied by time is the impulse, which means the change of momentum of the spaceship.
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    (Original post by pippabethan)
    okay, sorry, didn't read it properly; use f=ma for a for 1st spaceship, then suvat for dist, then work out stopping force to decelerate in 7200km, and use these values for total dist of 2nd spaceship
    For the second spaceship entering the cloud...

    From the previous question, the resistive force acting on the spaceship is 1.25N
    So,
    F=ma
    -1.25=5500a
    a= -0.00023

    u=60
    v=0
    a=-0.00023
    s=?

    So,
    v^2=u^2 + 2as
    0^2 = 60^2 + 2 x -0.00023 x s
    s = 7826086.97m


    Spaceship 1 dist. - spaceship 2 dist. =
    720,0000m - 7826086.957m
    =626086.9565m
    =626km

    Where am I going wrong, as the answer should be 655km?? Thankyou!
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    A spaceship of mass 5000kg is stationary in deep space. It fires its engine producing a forward thrust of 2000N for 2.5 mins, then turns them off. The spaceship then enters a cloud of interstellar dust which brings it to a halt after 7200km. The spaceship travels in convoy with another spaceship the same in all respects, except that it carries another 500kg equipment. Both carry out the same procedure. Which travels further into the dust cloud? !


    For the second spaceship entering the cloud...

    From the previous question, the resistive force acting on the spaceship is 1.25N
    So,
    F=ma
    -1.25=5500a
    a= -0.00023

    u=60
    v=0
    a=-0.00023
    s=?

    So,
    v^2=u^2 + 2as
    0^2 = 60^2 + 2 x -0.00023 x s
    s = 7826086.97m


    Spaceship 1 dist. - spaceship 2 dist. =
    720,0000m - 7826086.957m
    =626086.9565m
    =626km

    Where am I going wrong, as the answer should be 655km?? Thankyou!
 
 
 
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