What killed the Physicist - 1/2mv^2 or mv

Thread Starter


Joined Sep 5, 2010
A Physicist gets hit by a car and dies...

When she reaches the gates of Kingdom of Death, she is greeted by "Chitragupt" (The guy in Hindu Mythology who decides if you would go to Heaven or Hell depending on your Karma)...!!

But Chitragupt makes an exception in this case and says that irrespective of your Karma, I would allow you to go to Heaven if you answer the following correctly:

What killed You...?? Was it
"1/mv^2" that killed You OR was it "mv" that killed You...!!

If the answer is right, she goes to heaven else goes to hell...!! Our physicist needs help to reach heaven...!!

Request forum experts to please help explain the difference in this scenario...!!

Ofcourse, one difference is a vector scalar thing... But in the sense of causing hurt, what is more likely to cause hurt - KE or Momentum...??


Delta Prime

Joined Nov 15, 2019
Hello there :)

Fascinating! two diametrically opposed answers. Both are correct.
Neither. Force is not described by 1/2mv^2
or mv.


Joined Feb 24, 2006
The derivative of one is the other.
So does the derivative kill you or does the integral. I think most students would agree, that the integral is what kills you.


Joined Jan 18, 2008
It's 1/2mv^2 . Why else is is the American government spending unaccounted billions on kinetic weapons instead of momentum-based weapons. It is not an elastic collision.