## Types of Forces

### Force: How to Calculate Buoyancy Force

**Buoyancy** is the force that pushes upward on an object placed in a fluid (gas or liquid).

An object placed in a fluid (gas or liquid):

**Will float** if the buoyancy force acting on it is more than the weight of the object.

**Will sink** if the buoyancy force acting on it is more than the weight of the object.

**Will remain submerged** in the fluid if the buoyancy force acting on it is equal to the weight of the object.

**How to Measure the Buoyancy Force on an Object placed in Water.**

The diagram shows the bottom of a 2-L plastic soda bottle with a hole that a flexible drinking straw snugly fit in. The straw drains displaced water into an empty container.

**1. **Weigh the objects to be placed in the water.

**2. **Fill the large container with water so that the water’s surface is just below the straw as shown.

**3. **Place the object in the water and allow the displaced water to drain into the collecting container.

**4. **Weigh the collecting container and displaced water. Subtract the weight of the container and the answer is equal to the water’s buoyancy force pushing up on the object.

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**Another Method to Measure the Buoyancy Force on an Object Placed in Water.**

The buoyancy force is equal to the mass of displaced water x acceleration of gravity . The force unit will be newtons.