3. A 0.50-kg object moves in a horizontal circular track with a radius of 2.0 m. An external force of 3.0 N, always tangent to the track, causes the object to speed up as it goes around. If it starts from rest its speed at the end of one revolution is: (A) 9.8 m/s (B) 12.2 m/s (C) 15.8 m/s (D) 17.5 m/s (E) 21.0 m/s.