The position of a toy helicopter of mass 2.3 kg is given by a function, f(t) = (3.6 m/s4)thi + (2.8 m/s3)+3j + (7.9 m/s)tk (i) Calculate the velocity of the helicopter in terms of 2, j, and k in 3.9 seconds. (Keep it for now, you need to upload the whole solution later. Do NOT write this answer in the box below) (ii) What is the magnitude of the force (in Newtons) on the helicopter in 3.9 seconds? (Write down the answer for this question only in the box below)