Vehicles!

Here are three examples of questionable physics in movies involving vehicles.
Speed
A terrorist plants a bomb on a bus. The only way to save the bus from blowing up is to keep the bus moving at least 50 miles per hour. One problem, there is a huge gap in the road coming up. In an attempt to save the bus and the passengers, the driver gets the bus up to 70 miles per hour to jump the 50 foot gap. Amazingly, the bus makes it and everyone is saved. However, when real physics are involved, this tale is proven false. It would have been pulled down by gravity by at least 3.5 feet, meaning that it would have missed the gap. Even with a ramp to to keep gravity from ruining the jump, the maximum distance the bus could have jumped is 22 feet. Either way, the bus would have blown up with real physics.
 Transporter 2
In this movie, a man is forced to transfer a package for the bad guy so he won't kill the girl involved. However, someone is out to get him too. With a bomb strapped to the bottom of the car, the driver is able to do a barrel roll to get a crane to dislodge the bomb from the bottom of the car, saving his life. However, with a small passenger car, even with high speeds, a barrel roll would be impossible. Gravity would pull the car down on its roof, making the jump an ill advised risk.


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http://www.denofgeek.us/movies/18022/10-action-sequences-that-defy-the-laws-of-physics
Mission Impossible
This is a fun movie with lots of action sequences. With many car chases and lots of hand to hand combat, there is a lot to keep action fans excited. In one sequence, the hero and a bad guy jump motorcycles at each other and jump off and collide mid air before the bikes do. They both fall to the ground and continue fighting. With real life physics, they both would have suffered serious internal injuries, if not dying from the pressure of 350,000 N/m^2. Their fight afterwards would not have been able to happen, at least without a long pause and hospital visits. 

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