The phase of a simple harmonic motion

[Guillem_dlc]

Homework Statement

How can I calculate the initial phase in a simple harmonic motion if I only have the amplitude, frequency and angular velocity as data?

Homework Equations

The formula of the position, in fact they ask me to do the formula that allows to know the elongation depending on the type and for that I use the formula of the elongation.

The Attempt at a Solution

I am not able to take the initial phase

 

[Chandra Prayaga]

Please state the actual problem. If that is the only data given, then you cannot find the initial phase.

 

[Guillem_dlc]

Original statement:
At the end of a pier we place a body, we stretch it a length of 4 cm and let it oscillate freely. Write the function that allows you to know its elongation, speed and acceleration as a function of time if it vibrates with a frequency of 2 Hz. Graph these functions taking time values that allow knowing what happens in two complete oscillations.

 

[Chandra Prayaga]

I am a little confused by the first statement in the problem. What is stretched? Is it stretched by a length of 4 cm, or strtched to a length of 4 cm? Could you draw a diagram?

 

[Guillem_dlc]

I do not understand it either very well, but I thought that the 4cm are the amplitude. The problem is not that it is very clear

 

[Chandra Prayaga]

OK. So let us assume that you stretched something by 4 cm and let it go, and it is oscillating freely with a frequency of 2 Hz. So what is the value of the stretch at t = 0?