# Simple Query about Forces

jimmy42
If an object is only half in the water, so floating. Will its horizontal force be half of that if it was fully underwater?

Thanks.

## Answers and Replies

Mentor
What do you mean by "its horizontal force"?

jimmy42
So, the water will be pushing on it in the positive and negative X ( left and right ) direction. If there is a box floating then only the bottom part will feel this force, as they are both equal they will cancel out. That means the box will not move.

I know that the force acting in the Y direction, so up down will be different and can work that out. I just wanted to know if half the box is in the water does it follow that because half as much water is exposed to the box then the force is half as much as when it's fully in the water.

Thanks.

Mentor
So, the water will be pushing on it in the positive and negative X ( left and right ) direction. If there is a box floating then only the bottom part will feel this force, as they are both equal they will cancel out. That means the box will not move.
The net horizontal force exerted by the water on the object will be zero. However the water does exert an upward buoyant force on the object.

I know that the force acting in the Y direction, so up down will be different and can work that out. I just wanted to know if half the box is in the water does it follow that because half as much water is exposed to the box then the force is half as much as when it's fully in the water.
The buoyant force equals the weight of the displaced liquid (this is Archimedes' principle). So the buoyant force when half-submerged is half as much as when fully submerged.