Measuring Buoyancy: How to Calculate Upward Force

  • I
  • Thread starter thetexan
  • Start date
  • Tags
    Measuring
In summary, the conversation discusses the difficulty of pushing a beachball underwater due to the upward buoyant force, and the possibility of using the volume of the object and viscosity of the liquid to determine the buoyant force. It also mentions using Archimedes' principle or attaching a spring to the balloon to measure the buoyant force. The conversation concludes that the force needed to push the beachball underwater would be equal to the weight of the water displaced by the ball, minus the weight of the ball itself.
  • #1
thetexan
266
11
When I take a beachball and force it underwater it is almost impossible due to the upward force of the buoyancy. Is there a way to determine what that upward force is based on volume of the object, or viscosity of the liquid (including air and balloons).

How does one figure that? Since the weight of the object being "floated" is equal to the volume of the water displaced wouldn't the force to push the beach ball underwater equal to the weight of the water displaced by the ball in units of force instead of weight?

tex
 
Physics news on Phys.org
  • #2
thetexan said:
When I take a beachball and force it underwater it is almost impossible due to the upward force of the buoyancy. Is there a way to determine what that upward force is based on volume of the object, or viscosity of the liquid (including air and balloons).

How does one figure that? Since the weight of the object being "floated" is equal to the volume of the water displaced wouldn't the force to push the beach ball underwater equal to the weight of the water displaced by the ball in units of force instead of weight?

tex

Your question is confusing. Are you looking for a way to calculate the buoyant force, or are you trying to find a way to measure the buoyant force?

If the former, then I'll first ask you if you are familiar with Archimedes principle. If it is the latter, attach a spring to the balloon the measure the pull on the spring when they are all under water.

Zz.
 
  • #3
thetexan said:
wouldn't the force to push the beach ball underwater equal to the weight of the water displaced by the ball
Yes (minus the weight of the ball, negligible for a beach ball).
 
  • #4
The calculation of the weight of the displaced water should be about right. If you want accuracy, weigh the beachball and subtract it. Remember that the beachball is compressible, so it will displace less water than if you measure it's size in the air. (I don't know how big the difference is.)
 

1. What is buoyancy and why is it important to measure?

Buoyancy is the upward force exerted by a fluid on an object that is partially or fully submerged in it. It is important to measure because it helps us understand how objects behave in fluids and is essential in designing structures such as ships and submarines.

2. How do you calculate buoyancy?

Buoyancy can be calculated using Archimedes' principle, which states that the buoyant force on an object is equal to the weight of the fluid that the object displaces. This can be expressed mathematically as Fb = ρVg, where Fb is the buoyant force, ρ is the density of the fluid, V is the volume of the displaced fluid, and g is the acceleration due to gravity.

3. What factors affect buoyancy?

The buoyant force of an object is affected by the density of the fluid, the volume of the object, and the acceleration due to gravity. Objects with a lower density than the fluid will float, while objects with a higher density will sink. The more volume an object has, the more fluid it will displace and the greater the buoyant force will be. The acceleration due to gravity also plays a role, as it affects the weight of the fluid being displaced.

4. How is buoyancy measured in real-life situations?

In real-life situations, buoyancy is often measured using a device called a hydrometer. This instrument measures the density of a liquid by measuring the amount of water it displaces. The difference between the two readings is used to calculate the buoyant force exerted on the hydrometer.

5. What are some applications of measuring buoyancy?

Measuring buoyancy has numerous practical applications. For example, it is used in shipbuilding to ensure that a ship will float and not sink. It is also used in designing and operating submarines, hot air balloons, and other vessels that rely on buoyancy for lift. Additionally, understanding buoyancy is important in fields such as oceanography, marine biology, and engineering.

Similar threads

Volume's effect on buoyancy: Does pressure increase?
    • Introductory Physics Homework Help
Replies
11
Views
395
Buoyant force acting on an inverted glass in water
    • Introductory Physics Homework Help
3
Replies
79
Views
4K
Exploring the Relationship between Buoyancy Force and Gravitational Force
    • Introductory Physics Homework Help
Replies
5
Views
807
B Does Buoyancy Apply When Not Fully Submerged?
    • Classical Physics
Replies
7
Views
838
Understanding Buoyancy: Exploring the Complexities and Misconceptions
    • Other Physics Topics
2
Replies
48
Views
8K
Calculate the max speed at which a submarine rises/dives
    • Mechanical Engineering
Replies
5
Views
503
B About buoyancy and 2 equations
    • Other Physics Topics
Replies
6
Views
1K
I Thought experiment on buoyant forces on a system
    • Other Physics Topics
Replies
7
Views
1K
Buoyant Force Definition & Explanation - Archimedes' Principle
    • Other Physics Topics
Replies
1
Views
4K
I How much force to throw an object vertically?
    • Other Physics Topics
Replies
15
Views
3K

Hot Threads

Recent Insights

Back
Top