Calculating Time Constant for Spring Oscillations

  • Thread starter Thread starter guru
  • Start date Start date
  • Tags Tags
    Oscillations
Click For Summary
To calculate the time constant for spring oscillations, the time period is first determined using the formula T = 2π√(m/k), resulting in approximately 0.9809 seconds. The decay constant (λ) is found to be 1.019 s^-1, leading to a time constant (τ) of about 0.981 seconds. The amplitude after 31 oscillations is calculated using the formula A = A0e^(-λt), where the initial amplitude A0 is derived from the final amplitude of 2.8 cm. The calculations demonstrate the relationship between the damping effect and the oscillation period. Understanding these principles is crucial for analyzing damped oscillatory motion in springs.
guru
Messages
38
Reaction score
0
A spring with spring constant 11 N/m hangs from the ceiling. A .540kg ball is attached to the spring and allowed to come to rest. It is then pulled down 6.2cm and released.
I need to find the time constant if the ball's amplitude has decreased to 2.8cm after 31 oscillations.

I need help on how to approach this problem
 
Physics news on Phys.org
You have all the information you need to find the period of oscillation, do that. You also should have the governing equation for damped oscillatory motion. You know the amplitude of motion at 2 different times. Use that information to find your damping coefficient.

If you have more questions, please share with us what you have as for the equation of motion of a damped oscillator.
 


To calculate the time constant for spring oscillations, we can use the formula T = 2π√(m/k), where T is the time period, m is the mass attached to the spring, and k is the spring constant.

In this problem, the mass of the ball is 0.540kg and the spring constant is 11 N/m. To find the time constant, we need to first calculate the time period of the oscillation.

Step 1: Calculating the time period
To find the time period, we can use the formula T = 2π√(m/k). Plugging in the values, we get:
T = 2π√(0.540kg/11 N/m)
= 2π√(0.04909 kg/m)
= 0.9809 s

Step 2: Calculating the decay constant
The decay constant (λ) is equal to 1/T, where T is the time period. So, λ = 1/0.9809 = 1.019 s^-1

Step 3: Calculating the time constant
The time constant (τ) is equal to 1/λ. So, τ = 1/1.019 = 0.981 s

Step 4: Finding the amplitude after 31 oscillations
To find the amplitude after 31 oscillations, we can use the formula A = A0e^(-λt), where A is the amplitude, A0 is the initial amplitude, λ is the decay constant, and t is the number of oscillations.

Plugging in the values, we get:
2.8cm = A0e^(-1.019 s^-1 * 31 oscillations)
2.8cm = A0e^(-31.589 s^-1)
A0 = 2.8cm / e^(-31.589 s^-1)
A0 = 2.8cm / 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

Replies
1
Views
864
  • · Replies 15 ·
Replies
15
Views
5K
Replies
9
Views
2K
Replies
3
Views
1K
Replies
1
Views
1K
Replies
3
Views
815
Replies
1
Views
3K
Replies
17
Views
2K
Replies
4
Views
861
  • · Replies 18 ·
Replies
18
Views
3K