What is the difference between dry operating weight and dry operating mass? What is the difference between dry operating mass and dry operating weight in the context of rotorcraft?

What is the formula for converting mass to weight?
Weight is a force.

Mass is a property of matter. Acceleration makes mass produce a force. Specifically, a mass in the gravitational field of Earth effects a weight force on its support. The relation between both is the gravitational acceleration g, which is standardized to 9.80665 m/s² (approximately 32.174 ft/s²), as in Weight = Mass · g.