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Lunar lander velocity before hitting ground

  1. Jan 19, 2015 #1
    1. The problem statement, all variables and given/known data
    A lunar lander is descending toward the moon's surface. Until the lander reaches the surface, its height above the surface of the moon is given by y(t)=b−ct+dt2, where b = 770m is the initial height of the lander above the surface, c = 62.0m/s , and d = 1.02m/s2 .
    Part B: What is the velocity of the lunar lander before hitting the ground?

    2. Relevant equations


    3. The attempt at a solution
    quadratic formula to find x intercepts. I don't know how I'm supposed to get the velocity before it hits the ground that could be at any point.
     
  2. jcsd
  3. Jan 19, 2015 #2

    BvU

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    A matter of finding the pertaining relevant equation!
    Do you recognize this y(t)=b − c t + d t2 ? Or do I nudge a bit harder by pointing at ##y(t) =y_0 + v_0t + {1\over 2} a t^2 ## ? What is the corresponding ##v(t) = ... ## equation ?

    If all else fails, you can also apply ##v_y = {dy\over dt}## if that's familiar to you
     
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