일반물리학 1 — Rotation: Problem 45

45 The body in Fig. 10-30 is pivoted at O, and two forces act on it as shown. If \( r_1 = 1.30 \text{ m} \), \( r_2 = 2.15 \text{ m} \), \( F_1 = 4.20 \text{ N} \), \( F_2 = 4.90 \text{ N} \), \( \theta_1 = 75.0^\circ \), and \( \theta_2 = 60.0^\circ \), what is the net torque about the pivot?