"Contribution" is something you put in to the group effort; this can be a gift of, as they like to say at our church, your "time and talent," or your cash. "Employee contributions to the pension plan totalled $350,000 this year." "The community reacted to the disaster with contributions of every kind. Food, blankets, clothing, and piles of toys accumulated at the shelter. Schoolchildren held bake sales and car washes to raise money for disaster relief."
"Cooperation" means to work with others. Money is not involved. Actual work does not have to be involved; a mother brushing her child's hair might stay, "Will you please cooperate and hold still?"
[not a teacher]