What is the Period of Oscillation for a Spring Cut to One-Third Its Length?

  • Thread starter Thread starter LCSphysicist
  • Start date Start date
  • Tags Tags
    Oscillation Spring
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
3 replies · 2K views
LCSphysicist
Messages
644
Reaction score
163
Homework Statement
A non-deformed spring whose ends are fixed has a stiffness
x = 13 N/m. A small body of mass m = 25 g is attached at the point
removed from one of the ends by n = 1/3 of the spring's length. Neg-
lecting the mass of the spring, find the period of small longitudinal
oscillations of the body. The force of gravity is assumed to be absent.
Relevant Equations
All below.
I am not sure if i get the problem, but if i understand, we want to know the period of oscillations on a spring with length l/3.

If is this the right interpretation, i would say that the stiffness of the new the spring is k/n, where k is the stiffness of the former spring.
This based on the knowing that the displacement of the points of the spring is proportional to the distance of the end, so to one force :

f = f, kx = k'xn, k' = k/n

T = 2π√(n*m/k)
The answer is, actually
T = 2π√(n*(1-n)m/k)
Where am i wrong?

1594524961396.png
 
Last edited:
Physics news on Phys.org
anuttarasammyak said:
The answer you show is an imaginary number so I doubt it.
Oh i made a confusion, actually is 1 - n instead n - 1
 
LCSphysicist said:
we want to know the period of oscillations on a spring with length l/3.
What about the other 2/3 of the spring?
 
  • Like
Likes   Reactions: anuttarasammyak and LCSphysicist