A uniform meter rule of weight 100 N is pivoted at its center(50 cm mark). A 150 N weight is hanged at the 10 cm mark and a 250 N weight is hanged from the 70 cm mark. Draw the diagram of the arrangement and calculate (a) the total anti-clockwise torque about its center, (b) the total clockwise torque about the center, (c) the net torque on the ruler about its center, and (d) the distance from the center where a 100 N weight should be placed to keep the meter rule at equilibrium.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?