Clock Oscillation

  • #1

Homework Statement



A grandfather clock has a pendulum length of 0.7 m and a mass bob of 0.4 kg. A mass
of 2 kg falls 0.8 m in seven days, providing the energy necessary to keep the amplitude
(from equilibrium) of the pendulum oscillation steady at 0.03 rad. What is the Q of the
system?

Homework Equations



1) Q = [tex]\omega[/tex]R/2[tex]\beta[/tex]

2) Q = [tex]\omega[/tex]0/[tex]\Delta[/tex][tex]\omega[/tex]

The Attempt at a Solution



I figured only equation 1 would help me here, and I can re-arrange it as follows:

[tex]\beta[/tex] = b/2m (b = damping coefficient)

Then Q = m[tex]\omega[/tex]R/b

when amplitude D is a maximum, we can differenciate wrt [tex]\omega[/tex] to obtain maximum (i.e [tex]\omega[/tex]R)

[tex]\omega[/tex]R = sqrt([tex]\omega[/tex]20 - 2[tex]\beta[/tex]2)

re-arranging yields

Q = m sqrt([tex]\omega[/tex]20 - b2/2m2)/b

I'm kind of stuck because I don't know how to find the coefficient of damping b. Did I go in the wrong direction here? I know I have to use the information given about the pendulum dropping to find the flaw in the system, any help please?
 

Answers and Replies

  • #2
Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
Insights Author
12,117
155
While I'm not certain how to solve the problem, the 2 kg mass dropping tells us at what rate energy is added to the pendulum to overcome damping.

Also, the power dissipated due to damping is definitely related to b. If you can express that power in terms of b, you should be in good shape.
 

Related Threads on Clock Oscillation

Replies
0
Views
2K
Replies
2
Views
1K
Replies
1
Views
631
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
8
Views
5K
  • Last Post
Replies
5
Views
1K
  • Last Post
Replies
10
Views
4K
  • Last Post
Replies
2
Views
17K
  • Last Post
Replies
4
Views
4K
  • Last Post
Replies
1
Views
3K
Top