Mass flow rate is a measure of the amount of mass passing through a given point in a system per unit of time. It is commonly expressed in units such as kilograms per second (kg/s). This concept is crucial in various fields, including engineering and physics, as it helps in understanding how substances move in processes like combustion, fluid dynamics, and chemical reactions. In practical applications, mass flow rate can be calculated using the formula: mass flow rate = density × velocity × cross-sectional area. Here, density refers to the mass per unit volume of the substance, velocity is the speed at which the substance flows, and cross-sectional area is the area through which the substance is moving.