Thursday, August 04, 2011

My letter to Dan Neil

In Dan Neil's most recent car review in the WSJ he was commenting on the size and weight of the 2012 Mercedes-Benz CLS63 AMG, and wrote:
Automotive science has almost banished the M from the A=M/F (acceleration=mass/force) equation. No car as big and heavy as the Mercedes has the right to accelerate this hard.
I sent him an email:

I love your column (and your new appearance on The Car Show), and I'm sorry for the nitpick, but in your review of the CLS63 in today's paper you commented on automotive science almost banishing the mass term from the force equation. You had the intuition right, but the equation wrong. It should have been: A = F / M. For the same force, a more massive car accelerates slower, while a lighter car accelerates quicker.
Otherwise, thanks for keeping your reviews funny and informative.
Eli Lansey
The article on the site is corrected, with a note at the bottom:
Corrections & Amplifications
In physics, acceleration equals force divided by mass. An earlier version of this article incorrectly gave the equation as acceleration=mass/force.
Yet, no response from Mr. Neil, and no attribution in the Journal. I wonder how many people wrote to him about this.


  1. He must have known that it was F/M. The original sentence makes no sense if it was M/F. In that case, "No car not as big and heavy as an eighteen wheeler deserves to accelerate this hard."

  2. I said he got the intuition right, but he still had the equation wrong.