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

Inspired Group Title

The blocks shown are released from rest with spring unstretched. Pulley & horizontal surface are frictionless. If k=400 N/m and M=4.5 kg, what is maximum extension of spring? http://s3.amazonaws.com/answer-board-image/20071222120396333222723984175004973.jpg

  • one year ago
  • one year ago

  • This Question is Closed
  1. Shadowys Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    where are you stuck? during max extension, they are not moving. for M, \(\Sigma F_y= T-F_g=0\) \(T=F_g=4.5*9.8\) for 2M, \(\Sigma F_x= T-F_s=0\) \(F_s=T=4.5*9.8\) \(kx=4.5*9.8\) sub k and solve for x.

    • one year ago
  2. Vincent-Lyon.Fr Group Title
    Best Response
    You've already chosen the best response.
    Medals 0

    Hi! Careful: this assumption is not correct: "during max extension, they are not moving. for M, \(\Sigma F_y= T-F_g=0\)" Velocity is zero, but they are accelerating, so \(\Sigma F_y\) is not zero. Best way to solve this problem is to use conservation of mechanical energy.

    • one year ago
  3. Shadowys Group Title
    Best Response
    You've already chosen the best response.
    Medals 1

    ah. missed that. sorry. i was thinking that it was not SHM

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

    by the conservation of ME, since there is no potential energy, or kinetic energy, and setting that height of M as 0 at the very beginning, and that at the max extension, the velocities are zero, i.e. still no kinetic energy, \(0=\frac{1}{2} kx^2 + MgX\) sub it all in and this should do it.

    • 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.