Calculate the torque of a spinning object if your physics textbook doesn't give it to you. Torque is equal to force times radius and expressed in units of "newton meters." For example, if you have a tire with a radius of 1.4 meters experiencing a force of 16.2 newtons, you can calculate its torque as follows: torque = 1.4 * 16.2 = 22.68 newton meters.
Use mass and radius to calculate the object's moment of inertia, keeping in mind the equation I = 1/2 * M * R^2, where "M" is an object's mass in kilograms and "R" its radius in meters. For example, if your tire with radius 1.4 meters has a mass of 23.3 kilograms, you calculate its moment of inertia as follows: I = 1/2 * 23.3 * (1.4)^2 = .5 * 23.3 * 1.96 = 22.83 kilograms per meter squared.
Determine acceleration from torque and moment of inertia. Knowing that torque is equal to moment of inertia times acceleration, rewrite the equation to reflect that acceleration is simply torque divided by moment of inertia. The acceleration for the example tire, then, is: 22.68/22.83 = .99 radians per second squared.