Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Yahoo!

A rock dropped from a cliff covers one-third of its total distance to the ground in the last second of its fall. Air resistance is negligible. How high is the cliff?

  • one year ago
  • one year ago

  • This Question is Closed
  1. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    @experimentX @shubhamsrg @JFraser

    • one year ago
  2. JFraser
    Best Response
    You've already chosen the best response.
    Medals 0

    this is already in the physics group

    • one year ago
  3. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    Can u Check My answer i got h = 148.48 m

    • one year ago
  4. experimentX
    Best Response
    You've already chosen the best response.
    Medals 1

    s = 1/2 gt^2 ----------- v = 0 + g(t-1) now u = v then, 1/3 s = v(1) + 1/2 g(1)^2 s = 1/2 gt^2 ---------- from these two solve or 's' and 't' rest should be okay

    • one year ago
  5. AravindG
    Best Response
    You've already chosen the best response.
    Medals 0

    nicely explained @experimentX

    • one year ago
  6. experimentX
    Best Response
    You've already chosen the best response.
    Medals 1

    thanks!!

    • one year ago
  7. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    Ok....i Did by this way: h = 1/2 g t^2 Dn = u + a/2 (2n-1) h/3 = a/2(2t-1).....?

    • one year ago
  8. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    in the formula you used @Yahoo! 'n' is the nth second, in your case, n= t-1 .. you already know h= 1/2 gt^2 also h/3 =g/2 (2t -3) taking g=10, i get h=45..someone please confirm ?

    • one year ago
  9. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    But why Do we take t-1

    • one year ago
  10. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    last second right ? after t seconds are complete , the object doesnt travel further..

    • one year ago
  11. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    I am Silly....u r correct...i got it now....

    • one year ago
  12. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    thxxxx

    • one year ago
  13. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    i may be wrong in logic though.. let someone else make any correction if its there..

    • one year ago
  14. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    I think ur Logic is Correct...

    • one year ago
  15. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    But Lets Confirm..as u told..@sauravshakya

    • one year ago
  16. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    maybe not tagged correctly..allow me @sauravshakya

    • one year ago
  17. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    you got 148 right? by another plausible method, i am also getting 148, so that should be right,,my logic is thus, flawed//hmm..

    • one year ago
  18. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    here is what i did,, we h = 1/2 g t1 ^2 ....(1) where t1 is total time taken . let t2 be time before it comes to last second of the journey, thus t1 - t2 =1 => t2 = t1 -1....(2) we know h- h/3 = 1/2 g t2 ^2 2h/3 = 1/2 g t2 ^2 ...(3) using 1,2,and 3 eqns, we can solve for h, t1 and t2 .. by taking g=10, i approximately get h=148.4 something.. which should be the ans.. unless ofcorse,,there is some flaw in this also! :|

    • one year ago
  19. sauravshakya
    Best Response
    You've already chosen the best response.
    Medals 0

    This one looks correct

    • one year ago
  20. Yahoo!
    Best Response
    You've already chosen the best response.
    Medals 1

    But This one Luks Similar to 1st One @shubhamsrg

    • one year ago
  21. shubhamsrg
    Best Response
    You've already chosen the best response.
    Medals 2

    1st one ?

    • one year ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.