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!

Homework Help: Free fall help!

  1. Oct 19, 2009 #1
    1. The problem statement, all variables and given/known data
    a robot probe drops a camara off the rim of a 239 m high cliff on mars, where the freefall acceleration is -3.7 m/s^2. a. fiind the velocity wl wich the camara hits the ground. b. find the tiime required for it to hit the ground.

    2. Relevant equations

    vf^2= vi^2+2ad

    3. The attempt at a solution

    vf=? ned to find

  2. jcsd
  3. Oct 19, 2009 #2
    d is actually -239m since it's falling. which means starting from 239 m and falling down to 0m so the change is -239m. the vf you will then calculate is actually negative like the acceleration since, again, it is falling downwards on the y axis
  4. Oct 19, 2009 #3
    Looks good except your displacement should be negative, [tex]\Delta d=0-239m[/tex]

    That will make your value for [tex]v_f^2[/tex] positive and you should be able to proceed.
  5. Oct 19, 2009 #4
    tyvm!!! but i wanna just ask 1 more question... so then will the final velocity be negative?b/c it is falling
  6. Oct 19, 2009 #5
    yes the vf will be negative, like i said in my previous reply >_>
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook