Velocity is the third episode of the fourth season. It was released on 12 October 2007.
A car crash into a building has ties to street racing, and possibly a cold case which intrigues both the scientist and the wilder side in Charlie.
The more technical, precise term for what is usually simply referred to as 'speed'. Velocity includes a directional component.
At the end of the episode, a reference is made to the Riemann-hypothesis, which is the basis of "Prime Suspect", episode five of season one.
Immediately after the crash, the trunk is closed. After the first cut to Sam's body, the trunk is open. Then the camera angle shifts, showing two people walking by the closed trunk. The camera angle shifts again to show Kyle just getting out of an open trunk. There is no way the trunk could have opened and closed that fast.
When Charlie and Anita meet Larry on a bench, his right arm is on the back of the bench and he puts it down. When the camera switches to their left, his arm is still on the back of the bench. This continues for the first 3 shots from the left.
When Ray Galuski lists off various modern marvels, he includes "nuclear fusion" among them. Controlled nuclear fusion has not yet been achieved; nuclear power plants are powered by nuclear fission, not fusion.
[This appears on the beginning of the episode] 7000 revolutions per minute 1200 foot pounds of torque 420 horsepower 7 victims