No, if you are visiting for the 5-week session, you will not need a visa. Similarly, if you visit for both summer sessions and stay for a total of 10 weeks, you will not need a visa as well. You will need a passport that is valid for at least 6 months after your intended stay. When you arrive in the Lima airport, you will receive a document called “Tarjeta Andina de Migracion” (TAM) and a customs declaration form. The immigration officer will stamp your passport and write the number of the amount of days you are permitted to stay (Typically 60). The maximum stay for a tourist visa is 183 days. You will need to keep the TAM card for in-country travel purposes, and for returning to the airport on the day of your departure. It is an overall easy process. More information can be found here: http://www.limaeasy.com/peru-info/peruvian-visa#tourist-visa-peru-needed.