This sequel shows how East High School students spend summer; unsurprisingly, it involves high-energy pop songs. Zac Efron’s hoops-playing Troy and Vanessa Hudgens’ shy Gabriella reveal their relationship’s ups and downs on the sweetly tender “You Are the Music in Me” and the bittersweet “Gotta Go My Own Way”; Ashley Tisdale’s Sharpay, meanwhile, asserts herself with the gleefully bratty “Fabulous.” Ensemble tracks like the upbeat “All for One” and the rock-tinged “Work This Out” are sing-along-ready and powered by sunny vibes.