Question about simple harmonic motion

In summary, this conversation discusses a problem involving a square block mounted on an axle through its center, connected to a rigid wall by a spring. The block is initially at rest and is rotated by 3 degrees, resulting in SHM. The period of the SHM can be calculated using the restoring torque equation and considering the rotational inertia and spring constant. There are two distinct omegas involved, one for the orientation change rate and one for the forward trig function argument. The net torque can be found by setting it equal to -k*theta, where torque is force multiplied by the perpendicular distance from the axis of rotation.
  • #1
-=CN=-
2
0
A square block, with a mass of 3.40 kg and edge lengths d = 6.00 cm, is mounted on an axle through its center. A spring of spring constant k = 1190 N/m connects the block's upper corner with a rigid wall. Initially the spring is at its rest length. If the block is rotated by 3° and then released, what is the period of the resulting SHM?

What type of problem should this be treated as?
 
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  • #2
It oscillates by rotation ... it's called a torsional oscillator.
You look at "restoring torque" which returns the object
(which responds slowly due to its rotational Inertia) to
the equilibrium orientation angle.

set torque = I alpha , get torque as function of theta.
Now it should operationally look like an oscillator eq'n.

Be careful to keep the omega_(orientation_change_rate)
distinct from the omega_(forward trig function argument)
omega_ocr has amplitude 3 degrees, while
omega_tfa is multiplied by time.

Enjoy it, this one is fun!
 
  • #3
there are two different omegas? I'm slightly confused. I know for a torsion oscillator, period is usually found using T = (2*pi)*(I/kappa)^(1/2)
Inertia can be calculated...but how should I go about getting kappa, setting the net torque = -k*theta?
 
  • #4
Torque is force multiplied by perpendicular distance from axis of rotation.

Tau = -K(d/2)^2 @ sin@ =@ approx
 

Related to Question about simple harmonic motion

1. What is simple harmonic motion?

Simple harmonic motion is a type of periodic motion in which a system oscillates back and forth around a central equilibrium point. It is characterized by a sinusoidal wave and is caused by a restoring force that is proportional to the displacement from the equilibrium position.

2. What are some examples of simple harmonic motion?

Some examples of simple harmonic motion include a pendulum swinging back and forth, a mass-spring system oscillating, and a guitar string vibrating after being plucked.

3. How is simple harmonic motion different from other types of motion?

Unlike other types of motion, simple harmonic motion is characterized by its restoring force, which always acts toward the equilibrium position. This results in a repetitive back and forth motion around the equilibrium point.

4. What is the formula for calculating the period of simple harmonic motion?

The period of simple harmonic motion can be calculated using the formula T = 2π√(m/k), where T is the period, m is the mass of the object, and k is the spring constant.

5. How is simple harmonic motion related to energy?

Simple harmonic motion involves the conversion of potential energy to kinetic energy and back again as the system oscillates. The total energy of the system remains constant, with the potential energy being highest at the turning points and the kinetic energy being highest at the equilibrium point.

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