Posted by Krista on Thursday, March 15, 2012 at 12:36pm.
If you step on your car's brakes hard, the wheels stop turning (i.e., the wheels "lock") after 1.5 revolutions.
At the same constant acceleration, how many revolutions do the wheels make before stopping if your initial speed is twice as high?

Physics  bobpursley, Thursday, March 15, 2012 at 12:41pm
wf^2=wi^2+2A*displacement
A= wi^2/2(1.5rev)
if initial speed is the doubled, then w^2 term in the numerator is x4, so rev must be x4 to keep A constant.
so 4x1.5=6rev