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

Find the amplitude and frequency of the vibrations

1. Homework Statement
A 1.50-kg ball and a 2.00-kg ball are glued together with the lighter below the heavier one. The upper ball is attached to a vertical ideal spring of force constant 165 N/m, and the system is vibrating vertically with an amplitude of 15.0 cm. the glue connecting them breaks at the lowest point. Find the amplitude and frequency of the vibrations after the lower ball has come loose.

2. Homework Equations
w=sqr(k/m)
F=-kx

3. The Attempt at a Solution
The answer is 23.9cm but I don't see how the amplitude could be larger if mass is removed... Unless of course I misread the question...

I initially tried F=kx --> mg=kx --> x=0.12m
 
388
1
Just because there is no net force doesn't mean the object stops, if the system was horizontal then in the middle of the oscillation there would be no net force but the weights would certainly move. You want the work done by the spring pulling up to be cancelled by the work done by gravity pulling down and by the spring pushing down.
 

Related Threads for: Find the amplitude and frequency of the vibrations

Replies
1
Views
13K
Replies
1
Views
2K
Replies
15
Views
20K
Replies
1
Views
7K
  • Last Post
Replies
3
Views
8K
Replies
10
Views
690
  • Last Post
2
Replies
26
Views
17K
Top