1. The problem statement, all variables and given/known data A time-dependent force, F = 8i – 4tj N, 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 m/s? b) How far is the object from its initial position when its speed is 15 m/s? c) Through what total displacement has the object traveled at this moment? 2. Relevant equations F = ma vf = v0 + at 3. The attempt at a solution I took the mag of the F which is sq(80) = ma so: 8.9 = 2a, therefore a should be 4.47. Then I used vf = vo + at. It is at rest so vo = 0 so: 15 = 4.47t, t = 3.35 and it is incorrect. Can someone please tell me what I did wrong? thanks.