I think that AP Physics is far beyond his level of competence.
There is no difference at all in meaning, however "competence" is the most often used, as many are unfamiliar with the noun "competency" and sometimes consider it an incorrect form of the word.
Capability is the ability to perform actions. Competence is the ability to perform a specific task, action or function successfully. So if you use your capability with success it becomes your competence. ;-)
Competency is acquiring the determined quality and skill set for being well qualified physically and intellectually where as the set standard level or quality of being adequately or well qualified physically and intellectually is competence.
A definition of 'Competence': "Demonstrating the knowledge, skills, experience, and attributes necessary to carry out a defined function effectively." A definition of 'Competency': "The description of the knowledge, skills, experience and attributes necessary to carry out a defined function effectively." In other words competencies describe what has to be done and how well. Competence is doing the required things to the required standard. Competence in a job therefore means being competent at all aspects of each function (competency) required to be performed within the role. See http://www.customs.govt.nz/about/Careers/Requirements/Preparing+a+Competency+Based+CV+for+Job+Applicants/What+is+the+difference+between+Competencies+and+Competence.htm
Competence would be a ratio, Capacity is max amount, volume, etc..
Patricia A. Zapf has written: 'Evaluation of competence to stand trial' -- subject(s): Competency to stand trial, Forensic psychiatry, Mental Competency, Methods
Competencies are the KSA that distinguish superior performers from average performers.Competence is the ability to meet the basic requirementsto perform a job or task.eg: you talk about the level of competence that a person has at a task.
The word "competency" is pronounced as "kom-puh-tuhn-see" with the stress on the second syllable.
The preposition "in" is typically used after the word "competency." For example, one might say "She demonstrated competency in project management."
Some words that can be used in place of power are ability, competence, capability, and skill. Other synonyms for power are dynamism, potentiality, competency, aptitude, and talent.
It is with linguistic competence that I am able to string together two sentences. Similarly, it is with technological competence that I am able to post them on the internet. To question the competence of my ability to use the word "competence"' in two sentences only highlights my incompetence at building your confidence in me. The status of my competence relies on building your confidence in my abilities, immediately, if not sooner.
He demonstrated his competence with his sure actions. They questioned his competence in dealing with the demonstrators.