일반물리학 1 — Force and Motion-I: Problem 9

9 In an xy plane, a 0.450 kg object moves in such a way that \( x(t) = -16.0 + 3.00 t - 5.00 t^3 \) and \( y(t) = 26.0 + 8.00t - 10.0t^2 \), where x and y are measured in meters and t in seconds. At \( t = 0.800 \text{ s} \), find (a) the magnitude and (b) the angle, relative to the positive direction of the x axis, of the net force on the object, and (c) the angle of the object’s travel direction.