name the factors that affect upthrust

When a system expels mass in one direction with acceleration, the accelerated mass will cause an equal and opposite force to the system because of Newton’s 3^rd law of motion, this reaction force is called Thrust. E.g. Exhaust gases coming out of a rocket creates a thrust on the rocket to lift it up

However, thrust is also used in other sense also sometimes a force acting perpendicular to a body is also termed as thrust (like buoyant force).