1. The problem statement, all variables and given/known data A time-dependent force, F = (8.00i – 4.00tj) N, where t is in seconds, is exerted on a 2.00-kg object initially at rest. (a) At what time will the object be moving with a speed of 15.0 m/s? (b) How far is the object from its initial position when its speed is 15.0 m/s? (c) Through what total displacement has the object traveled at this moment? 2. Relevant equations F = ma a = d/t 3. The attempt at a solution (a) F = ma (8.00i – 4.00tj) N = (2.00 kg)(15.0 m/s) t = 2s (b) a = d/t (15.0 m/s2)(t) = d I don't see why it's not 2 seconds. Is it not just algebra, did I leave out a significant part of the equation? Thanks, this site has taught me quite a bit.