Tradução:Eu tentei abrir a porta com toda a minha força.
Sei não, imagina a frase "may the strenght be with you"... Ia soar estranho :P! Falando sério agora, eis uma explicação bastante interessante retirada deste site (http://www.usingenglish.com/forum/threads/162894-force-vs-strength):
"Force" can be a verb (to use a lot of effort to do something: he forced open the door), a noun (something powerful that alters something else: he was a positive force in the community; use the force, Luke!), or refer to the military (the air force; the armed forces).
"Strength" is a noun only. (Its adjective form is strong.) It can mean the quantity of any of the forces mentioned above (the strength of the armed forces = the number of personnel), someone's capacity to do something, especially physical or muscular (he didn't have the strength to walk farther; I lift weights to increase my strength), or someone's inner will or determination (he called upon his inner strength to keep smiling; God, give me the strength to stay awake in Church!).
E algo mais simples, direto de Star Wars (http://uk.answers.yahoo.com/question/index?qid=20110504121859AAq3uGF): Force is the power
Strength is the measurement of it
Hope that helped!