How to say a verb has 'acted' on something

Question

I am trying to figure out how to say how something/someone has done something or has had something happen to them in Spanish.

I am not sure how to put this properly, so here is an example:

A string has to vibrate so that a sound can be created.

Here is how I would write this:

Una cuerda tiene que reverberar asi que un sonido puede ser creado.

Did I use 'creado' correctly? If I wanted to say a subject had been hit, or had been created, how do I take the verb golpear or crear and transform it into 'had been hit/created'?

Answer 1

In Spanish impersonal “se” constructions often serve the same purpose as the passive voice. Two literal translations of your sentence would be

Una cuerda tiene que vibrar para que se pueda crear un sonido

Una cuerda tiene que vibrar para que pueda crearse un sonido

But a more idiomatic sentence would be

Una cuerda debe vibrar para poder producir un sonido

A string must vibrate to be able to produce a sound

Answer 2

I think that what you're looking for is the Spanish equivalent of the English past participle

According to the Cambridge Dictionary

the form of a verb, usually made by adding -ed, used in some grammatical structures such as the passive and the present perfect.

That equivalent is the participio

According to the D.R.A.E

participio

2. m. Gram. Forma no personal del verbo, asimilada frecuentemente al adjetivo en su funcionamiento gramatical, que es susceptible de recibir marcas de género y número y de participar en la formación de pasivas y otras perífrasis verbales.

participio activo

2. m. Gram. participio que funciona como adjetivo y que se refiere al sustantivo como agente de la acción verbal; p. ej., asomada en La niña está asomada a la ventana.

I've highlighted in bold the part that matches what you have stated in the title of your question: a verb has 'acted' on something.

creado is the participio of the verb crear
golpeado is the participio of the verb golpear

As @arielCo has pointed the right translation of "so that" in your phrase is "para que", "así que" is not idiomatic in your context.