If you step on your car's brakes hard, the wheels stop turning (i.e., the wheels "lock") after 1.5 revolutions.

Question

At the same constant acceleration, how many revolutions do the wheels make before stopping if your initial speed is twice as high?

Answer 1

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