The physics of gears and pulleys with a specificity of class B levers in terms of mechanical advantage. Here are some notes regarding the relationship between angular velocity, linear velocity (around the circumference), mechanical advantage in terms of a Class B lever, and stress vs strain: Angular Velocity: Velocity of the angle; similar triangles Linear Velocity: Velocity around the circumference Mechanical Advantage: The ratio of the edges of the circles; directly proportional with the force being applied to the outer circle(unless explicitly noted) as in a Class B lever. Note that in a Class C lever the ratio would be reversed. Stress vs Strain: As the force increases, distance decreases; torque. Increased force results in higher stress, but less work interval(time in between). By the rules of torque the same can be said for increasing distance and decreasing force.