• Support PF! Buy your school textbooks, materials and every day products Here!

Find the displacement from equilibrium after some time

  • #1

Homework Statement


A 50 lb weight is attached to the end of a spring. The spring is stretched 6 inches. Find the displacement from equilibrium of the weight after (π/8) seconds, if the weight is released from a point 2 inches above the equilibrium position. Round to the nearest length of a foot.

Homework Equations


(d2/dt2) + (k/m)x =0
mass m = w/g, where g = 32 ft/s2
F=ks, where k is the spring constant and s is how much the spring is stretched​

The Attempt at a Solution


My professor says that the answer is 0.2 ft. However, I am getting 0.11 ft.
attempt.jpg

 

Attachments

Answers and Replies

  • #2
Orodruin
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
16,682
6,462
In the future, please type out your attempt instead of just attaching an image of your work. (See the homework guidelines, item 5.)

What happened here?
upload_2018-7-11_7-56-24.png


In general, you should try not to insert numbers in the beginning of your solution - it makes it easy for errors to propagate without any easy means of checking your computations other than checking every single step. Give names to your knowns and unknowns and keep them until you have an expression for your sought quantity in terms of known quantities. Then, and only then, should you start inserting numerical values.
 

Attachments

  • #3
Chandra Prayaga
Science Advisor
649
148
Isn't something wrong in your calculation of the spring cpnstant?
 

Related Threads on Find the displacement from equilibrium after some time

Replies
10
Views
5K
Replies
5
Views
701
Replies
7
Views
901
Replies
6
Views
4K
Replies
2
Views
4K
Replies
10
Views
2K
Replies
5
Views
2K
Replies
4
Views
2K
Top