[masraum]

Originally Posted by hbueno

F=ma

Weight is force F, which is the product of mass x acceleration.

The weight is less underwater because the buoyant force is pushing up while gravity is pulling down.

It's all about definitions.

Is an item's weight what you can measure with a scale?
Is an item's weight what you calculate using a known mass and a known gravitational constant, then the bouyant effect from water doesn't matter. (net weight vs gross).
If we are going to use W=mg, then are we considering ONLY g (like above) or are we looking at a free body diagram of forces.