Force f -90 n i 50 n j acts on a particle with position

Question

Force F = (-9.0 N) i + (5.0 N) j acts on a particle with position vector r = (-5.0 m) j + (1.0 m) k .

(a) What is the torque on the particle about the origin?

(b) What is the angle between the directions of r and F? (If there is no torque, enter 0.)

(c) What is the angle between the directions of force and torque? If there is no torque, enter 0.