By John Young
Updated June 26, 2011 at 06:34 PM EDT

Ka-ching! Disney and Pixar’s Cars 2 shook off conservative industry projections and wound up opening to a hearty $68 million, according to studio estimates. While that’s by no means the strongest debut for a Pixar film, Cars 2‘s performance should come as something of a relief to the animation powerhouse since some industry experts were predicting a debut closer to $50 million. Among all 12 Pixar movies, Cars 2‘s opening ranks fifth. When adjusted for ticket-price inflation, it drops down to ninth. The original Cars debuted to $60.1 million in 2006, or about $72 million in today’s dollars.

It’s a bit hard to gauge moviegoers’ response to the $200 million automotive sequel. CinemaScore audiences gave it a strong “A-” grade, which should indicate positive word of mouth. However, Cars 2 dropped 9 percent from Friday to Saturday. Family films usually grow from Friday to Saturday, so this decline is a bit concerning. Part of the problem may have been the G-rated film’s mediocre reviews, which potentially scared off some childless adults. Or Cars 2 was simply front-loaded thanks to families with young boys demanding to see the movie right away. As for Hollywood’s current 3-D funk, Cars 2 didn’t provide any relief. According to Disney, 40 percent of the film’s gross came from 3-D screenings, making Cars 2 the fourth straight major release (after Pirates of the Caribbean: On Stranger Tides, Kung Fu Panda 2, and Green Lantern) to earn less than half of its opening from 3-D theaters. Hollywood is hoping that next week’s Transformers: Dark of the Moon breaks the trend.

In second place, Bad Teacher became the summer season’s third R-rated comedy hit, joining The Hangover Part II and Bridesmaids. The Cameron Diaz movie took in $31 million, beating Bridesmaids‘ $26.2 million opening. Both movies relied on support from female moviegoers — women made up 63 percent of Bad Teacher‘s audience. However, like Cars 2, the film slipped from Friday to Saturday, falling 10 percent. And CinemaScore graders weren’t nearly as kind, handing the comedy a tepid “C+” rating. In other words, don’t expect Bad Teacher to match Bridesmaids‘ incredible box-office legs. But considering the picture cost only $20 million to produce, the end result will surely look good on Sony’s report card.

Warner Bros., on the other hand, will have to live with the blemish that is Green Lantern. The Ryan Reynolds superhero flick dropped 66 percent for $18.4 million. After two weekends, the $200 million movie has collected only $89.3 million. Finally, both the sci-fi adventure Super 8 and the Jim Carrey family comedy Mr. Popper’s Penguins fell 44 percent this weekend, making $12.1 million and $10.3 million, respectively.

In limited release, the documentary Conan O’Brien Can’t Stop grossed $105,000 from 24 locations — a disappointing per-theater average of $4,375. And the immigrant drama A Better Life earned a decent $60,000 from four theaters. Check back next week as Transformers: Dark of the Moon makes mincemeat out of the Tom Hanks-Julia Roberts comedy Larry Crowne and the Selena Gomez comedy Monte Carlo.

1. Cars 2 — $68.0 mil

2. Bad Teacher — $31.0 mil

3. Green Lantern — $18.4 mil

4. Super 8 — $12.1 mil

5. Mr. Popper’s Penguins — $10.3 mil