1.The position vector of a 3000N helicopter is given by: r=(.02 m/(s^3))(t^3)i + (2.2m/s)tj - (0.06 m/(s^2))(t^2)k Find the net force on the helicopter at t = 5s. 2. I really have no clue where to begin. 3. I started doing this: r= (.02m/(s^3))(5s^3)i + (2.2m/s)(5s)j - (.06m/(s^2)*(5s)^2k r= 2.5mi + 11m + 1.5m then I drew a 3d graph with each axis labeled and two right triangles but have no clue where to go from here.