Answer to Question #17436 in Mechanics | Relativity for hugyu
A bullet moving with a speed 'v' can just penetrate two planks of equal thickness. Find the number of such planks that the bullet will penetrate if its speed is doubled.
The energy of the bullet will increase
N =& (m(2V)²/2) / (mV²/2) = (2V)² / V² = 4
times if its speed is doubled. So, the bullet will penetrate 4 times more planks, that is
M = 2*4 = 8