Upthrust, also known as buoyant force, depends on two main factors as identified in the reference: the volume of the body submerged in the liquid and the density of the liquid it is submerged in.
Factors Affecting Upthrust
Here's a detailed look at how each factor influences upthrust:
1. Volume of the Body Submerged
- Direct Relationship: The greater the volume of an object submerged in a liquid, the greater the upthrust experienced.
- Explanation: A larger submerged volume displaces a greater amount of liquid. This displaced liquid's weight is equal to the upthrust.
- Example: A large ship floats because it displaces a very large volume of water, which generates a substantial upthrust to counteract its weight.
2. Density of the Liquid
- Direct Relationship: The denser the liquid, the greater the upthrust.
- Explanation: Denser liquids weigh more per unit volume. Therefore, when a body displaces a certain volume of a denser liquid, the weight of the displaced liquid is greater, thus increasing the upthrust.
- Example: It's easier to float in salt water (more dense) than in fresh water.
Upthrust Formula
The reference also provides the formula for upthrust:
Upthrust = Volume of body × Density of liquid × Acceleration due to gravity
Where:
- Volume of the body: The submerged volume of the object.
- Density of the liquid: The mass per unit volume of the liquid.
- Acceleration due to gravity: The gravitational force that acts on the object.
Summary Table
| Factor | Impact on Upthrust | Explanation |
|---|---|---|
| Volume of Submerged Body | Greater Upthrust | A larger submerged volume displaces more liquid, resulting in a greater buoyant force. |
| Density of the Liquid | Greater Upthrust | Denser liquids provide more weight for a given volume of displaced fluid, thus increasing the upward buoyant force. |
Practical Insights
- Floating and Sinking: An object floats when the upthrust is equal to or greater than its weight. Conversely, an object sinks if its weight exceeds the upthrust.
- Submarines: Submarines control their buoyancy by adjusting their density, taking in or expelling water from ballast tanks to submerge or float.
