Find velocity from Force graph using Work Theorem and Energy

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
5 replies · 2K views
Max
Messages
9
Reaction score
0

Homework Statement

:[/B]

upload_2017-4-15_0-58-8.png

upload_2017-4-15_0-58-45.png


upload_2017-4-15_0-59-59.png

Homework Equations

W= \integral(Fxdx) W = \delta KE

The Attempt at a Solution


I used the definition of work to find the final velocity at 2m, and then work theorem together with integration for the changing force. I ended up having different solutions at first but then attempted to find acceleration instead for the constant force, and then plugged into find time it took it to reach 2m.
Then I used that data to find final velocity at 3m. It turned out very well. I just didn't understand why my first solution was wrong,
 

Attachments

  • Screenshot (1).png
    Screenshot (1).png
    7.3 KB · Views: 538
Last edited by a moderator:
Physics news on Phys.org
Max said:
Then I used that data to find final velocity at 3m. It turned out very well. I just didn't understand why my first solution was wrong,
If you show us exactly what you did and how you calculated your first solution, we should be able to help you.
 
I found out the error! I copied the graph wrongly so when I plugged in for integration, it was off! Jesus! Thanks though. Next time, I will post my handwritten note!
 
Max said:
Next time, I will post my handwritten note!
Better yet, familiarize yourself with LaTeX and use it instead of handwritten notes.

BTW, (belatedly) welcome to PF.
 
  • Like
Likes   Reactions: Max
kuruman said:
Better yet, familiarize yourself with LaTeX and use it instead of handwritten notes.

BTW, (belatedly) welcome to PF.
I downloaded Latex as you suggested but not sure how it works. It was an over 1Gb download
 
Max said:
I downloaded Latex as you suggested but not sure how it works. It was an over 1Gb download
Sorry, you misunderstood me. You didn't have to download LaTeX, although it will come in handy for work that is not PF related. You can embed LaTeX equations directly into the PF pages and there is a nifty quick guide to get you started. Just click LaTeX near the bottom of the page, all the way to the left from UPLOAD and to the right of the question mark. This will get you started. The LaTeX you downloaded, save for later use. It's great for writing papers, reports and anything that requires a lot of equations.