At time t = 0, a 2.0 kg particle has position vector r = (4.0m) i -

Question:

At time t = 0, a 2.0 kg particle has position vector r = (4.0m) i - (2.0 m) j relative to the origin. Its velocity is given by v = (-6.0t2 m/s) i for t > 0 in seconds. About the origin, what are?
(a) The particle's angular momentum i and
(b) The torque r acting on the particle, both in unit-vector notation and for t > 0? About the point (-2.0 m, -3.0 m, 0), what are
(c) L and
(d) r for t > 0?