Ok in addition to my other post for help i have some other problems puzzling me. 1)A wagon wheel is constructed as shown in the figure. The radius of the wheel is 0.300 m, and the rim has mass 1.49 kg . Each of the eight spokes, that lie along a diameter and are 0.300 m long, has mass 0.220 kg. What is the moment of inertia of the wheel about an axis through its center and perpendicular to the plane of the wheel? Ok i know that the moment of inertia of just the outer rim is MR^2 but how do i take into account the Moment of inertia of the eight spokes? I tried treating the spokes as if they were rods and using ML^2/12 and multiplying by 8 for the eight spokes but my answer came out wrong? so how is it supposed to be? 2) A uniform, solid disk with mass m and radius R is pivoted about a horizontal axis through its center. A small object of the same mass m is glued to the rim of the disk. If the disk is released from rest with the small object at the end of a horizontal radius, find the angular speed when the small object is directly below the axis. I have no idea where to begin on this any hints or tips? 3)A square metal plate 0.180 m on each side is pivoted about an axis through point O at its center and perpendicular to the plate Calculate the net torque about this axis due to the three forces shown in the figure if the magnitudes of the forces are F_1=18.0N, F_2=24.0N, and F_3=14.0N. The plate and all forces are in the plane of the page. Take positive torques to be counterclockwise. Ok so i know that the effective lever arm r is perpendicular to O so for torque_1 is did T_1=18.0N*.09m=2.34 N*m and for T_2 similarly i did T_2=24N*.09m=1.62N*m but for T3 im stuck.... after i found all the individual torquest are they simply added together for net torque or must i multiply by and angle between them all? 4) A grindstone in the shape of a solid disk with diameter 0.460m and a mass of = 50.0kg is rotating at omega = 840 rev/min . You press an axe against the rim with a normal force of F = 220N, and the grindstone comes to rest in 7.00s . Ok i thought this one was going to be easy but i was wrong. I tried using W_other=-K1 since my other works canceled out. i converted omega into rad/s and for K1 i got -5116J. W_other should be the force times the distance it was done at correct? what i did was soemthing like d=r*t but i did d=omega*t and also tried using the tangent v=omega*r to find the distance that the friciton force acts to get its work. Anyone see where im goin wrong or have a better method on this one?