Here is a problem from my book: If a car rolls gently (initial velocity = 0) off a vertical cliff, how long does it take to reach 90km/h? It seems easy, and I have been breezing through all teh other ones like it's my job, but for some reason this one gets me. I knwo it's possible, but I jsut don't know how. The answer is supposed to be 2.6 seconds, but I somehow always wind up dividing 90 by 9.8. Any help?