Finally Using My Mechanical Engineering Degree in Analyzing Law–A “Joule” of an Argument in the Michael Dunn Trial

I normally discuss matters of contract law on this blog. However, the law of contracts is not the only subject of my academic inquiry.  I will be teaching a class in Firearms Law in the spring 2015 term–focusing on matters such as the Second Amendment. I’m not entirely surprised that the class has three times the scheduled enrollment as that in my advanced contracts class.

In reviewing the Michael Dunn (the loud music) trial, I came across the following in the prosecution’s closing argument, as captured on a youtube video. I will discuss it because it raises issues of firearms as well as material in the scope of my prior study of mechanical engineering at M.I.T.

More after the break ….

Let us first turn to a part of the judge’s observations preceding the closing argument:


Judge Russell L. Healey, at 4:42-4:51.

… But you should listen very carefully to their arguments.  The arguments are intended to aid you in understanding the case and the law that I will instruct you on.

As we shall see, part of the prosecution’s argument would not “aid … in understanding the case”:

Prosecution’s Closing Argument, at 1:30:42-1:30:50:

Reasons the defendant is guilty of all the crimes he is charged with: …

at 1:32:16 to 1:33:06

The way he shot his gun. The number of shots. Ten. Three when the car is fleeing. The actual pattern of shots. He wasn’t shaking out of fear. He had steady hands when he hit Jordan’s door three times. The only reason the rest of the shots are spread out is because Tommy Stornes is driving for his life.

6.25 pounds for each trigger pull. 6.25 pounds. That’s over 60 pounds of pressure he had to use and exert to get off 10 shots. That gun didn’t fire itself.

Michael Dunn Trial, Day 6, Part 2, Prosecution Closing Arguments
video at

So, what’s the problem? Well, of course, the prosecutor is not talking about pressure at all. Pressure is force per unit area, as in a tire pressure of 32 pounds per square inch.  So she’s really discussing force, not pressure. Fine. No big deal.

The patent error is making reference to “over 60 pounds”. I believe it would be very difficult for me to apply 60 pounds of pressure with my index finger. The reader is cordially invited to attempt to pick up a mere 25 pound weight at his local gym with his index finger.

As it turns out, my Contracts casebook is perhaps 4.5 pounds. I have picked it up 180 times over the recently concluded academic year with my right hand, to take it to class and return it to my office. I believe all would concur that I cannot casually apply 810 pounds (4.5 x 180) of force with my right hand in picking up something.

One supposes that one with a firearm having a 6.5 pound trigger might on occasion shoot 100 rounds during a practice session (sometimes more, sometimes fewer). Does that mean the person can apply 650 pounds of force with his index finger? No, of course not.

I suppose that what she was attempting to address was the work necessary to displace the trigger multiple times, overcoming the resistance of the spring. But, in any case, to be clear, it does not take 60 pounds of force to actuate the trigger ten times; and, to say it does is inherently misleading, because it suggests an application of force that represents a level of effort grossly in excess of what is necessary to actuate the trigger (whether one or ten times).

A “joule” of an argument provided by the prosecution (please excuse the engineer’s pun).