Task: Translation
Input (English): English sentence: He also took courses in experimental physics, which were compulsory, and he began to plan to undertake research in relativity.
Output (Tagalog): Siya rin ang mga kursong kinuha sa experimental physics, na kung saan ay sapilitan, at siya ay nagsimulang plano upang magsagawa ng pananaliksik sa kapamanggitan.