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

Spring equilibrium problem

  • Thread starter starhallie
  • Start date
  • #1
16
0

Homework Statement



A 2kg object is suspended from a vertical spring that has a constant of 180N/m.

a) How far does the spring stretch from the unstrained length?

b) If the object is now pulled downward an additional distance of 5cm. What external force was required to do so?

c) When the object is released from rest, it begins to move upwards. Find the maximum speed that the object reaches and the maximum height above the release point at which the object releases direction.

Homework Equations



Fspring= kx

The Attempt at a Solution



I would be grateful if someone could check my answers to parts a & b and possibly steer me in the right direction on part c?

a) Fspring= kx
F=ma
ma=kx
x= ma/k
=(2kg)(9.8 m/s2)/(180 N/m)
= 0.1089m

b) Fspring= kx
=(180 N/m)(0.05cm)
= 9 N
 

Answers and Replies

  • #2
rl.bhat
Homework Helper
4,433
5
In the case b, find the elastic potential energy stored in the spring.
After releasing when it crosses the position in case a, it will have the maximum kinetic energy and gravitational potential energy. Apply the conservation of energy to find the maximum velocity.
 
  • #3
16
0
Thanks for your help :smile:

This is what I got so far...

PEspring= 1/2kw2= 1/2(180 N/m)(0.05m)= 0.225 J

... but I'm having trouble understanding the rest.
 
  • #4
rl.bhat
Homework Helper
4,433
5
At a position total energy = 1/2*m*v^2 + mgh
Find vmax
 
  • #5
16
0
Thank you very much for your help!
 

Related Threads for: Spring equilibrium problem

  • Last Post
Replies
3
Views
6K
  • Last Post
Replies
4
Views
2K
  • Last Post
3
Replies
57
Views
2K
  • Last Post
Replies
2
Views
554
Replies
9
Views
1K
  • Last Post
Replies
4
Views
8K
  • Last Post
Replies
1
Views
6K
Replies
1
Views
19K
Top