1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    Science Advisor
    Homework Helper
    2017 Award

    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
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted