15. Questions 15 and 16 are related to the situation shown. A rod [weight 20 N; F that is, my = 20 N) that can rotate about its bottom end is oriented as shown. The rod is uniform, so the force of gravity acts at its geometric center, and there is another force F = 15 N acting on it as shown. Which equation is easier to use to calculate the net torque caused by the two forces about the pivot indicated? 3.0 m A. I = Fir B. T = Fri mg 16. Use the equation you identified in question 15 to calculate the net torque 1.5 m ca used by the two forces about the pivot indicated. DO NOT use Fr sin 6! You will get the wrong answer. Express your answer in Nm and input the number only. If your answer is negative, input the negative sign. Hint: Don't forget about the signs! For each force, first, think about whether it creates positive or negative torque. Also, think carefully about what perpendicular distance to use. Drawing the line of force for each of the two forces may help. F 17. Suppose force F acts upwards as shown. Calculate the net torque in this situation. Express your answer in Nm and input the number only. If your answer is negative, input the negative sign. Hint: Don't forget about the signs! For each force, first, think about whether it creates positive or negative torque. Also, think carefully about what perpendicular distance to use. Drawing the line of force for each of the two forces may help. 3 0 m mg 1.5 m