At time t, r→ = 9.80t2 i^ − (7.60t + 3.70t2)j^ gives the position of a 3.0 kg particle relative to the origin of an xy coordinate system (r→ is in meters and t is in seconds). (a) Find the torque acting on the particle relative to the origin at the moment 4.75 s (b) Is the magnitude of the particle's angular momentum relative to the origin increasing, decreasing, or unchanging? (a) k Units (b)