Thanks, but what has got me baffled is how can I find the velocity or acceleration without the time? I tried F=mv2/r →3.6N=((.0012kg)v2)/0.38m and got the answer 33.76 m/s which is wrong according to the back of the book (answer given is 17 m/s). Okay, I found an explanation on (sadly) Yahoo...
Homework Statement
A 1.2 g pebble is lodged in the tread of a 0.76-m automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire tread...