Hydrostatics and fluid mechanics

• Lorna18
In summary, the problem involves a glass cube of length 2cm and specific gravity=3 that is half immersed in water with a surface tension of 75 dynes/cm. The goal is to find the reading shown by the spring balance, with a contact angle of 0 degrees and a gravitational acceleration of 1000cm/sec^2. The attempted solution uses the volume of the cube and the weight of the displaced water to calculate a surface tension force of 0.2 gm wt.
Lorna18

Homework Statement

A glass cube of length 2cm and specific gravity=3 is kept suspended via a spring balance and is kept exactly half immersed in water. surface tension of water is 75 dynes/cm. find the reading shown by the spring balance. (contact angle = 0 degree. g=1000cm/sec^2)
i got 23.8 gm wt but the answer seems to be wrong

The Attempt at a Solution

vol of glass cube = 8cm^3
vol of the part immersed is 4m^3weight of water displaced = 4*1gm wt

Welcome to PF!

Hi Lorna18! Welcome to PF!
Lorna18 said:
A glass cube of length 2cm and specific gravity=3 is kept suspended via a spring balance and is kept exactly half immersed in water. surface tension of water is 75 dynes/cm. find the reading shown by the spring balance. (contact angle = 0 degree. g=1000cm/sec^2)
i got 23.8 gm wt but the answer seems to be wrong

You seem to have a surface tension force of 0.2 gm wt …

how did you get that?

1. What is the difference between hydrostatics and fluid mechanics?

Hydrostatics is the study of fluids at rest, while fluid mechanics is the study of fluids in motion. Hydrostatics deals with the pressure and forces exerted by fluids on stationary objects, while fluid mechanics deals with the behavior of fluids in motion, including topics like fluid flow, turbulence, and viscosity.

2. How does hydrostatic pressure vary with depth?

According to Pascal's principle, the pressure in a fluid at rest increases with depth. This is due to the weight of the fluid above pushing down on the layers below. The increase in pressure with depth is directly proportional to the density of the fluid and the acceleration due to gravity.

3. What is Archimedes' principle?

Archimedes' principle states that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid that the object displaces. This explains why objects float in fluids - if the weight of the displaced fluid is greater than the weight of the object, it will float, and if it is less, the object will sink.

4. How does Bernoulli's equation relate to fluid mechanics?

Bernoulli's equation describes the relationship between pressure, velocity, and height in a fluid. It states that as the velocity of a fluid increases, its pressure decreases, and vice versa. This principle is important in understanding the flow of fluids in pipes, pumps, and other systems.

5. What are some real-world applications of fluid mechanics?

Fluid mechanics has many real-world applications, including in engineering fields such as aerospace, civil, and mechanical. It is used to design and optimize aircraft and car aerodynamics, as well as in the design of water and sewage systems. It is also important in the study of weather patterns and ocean currents, and in the development of medical devices such as ventilators and blood flow meters.

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