Nwebie,formula for drag of submerged object

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To calculate the drag of a submerged object like a styrofoam rectangle, the drag force can be estimated using fluid dynamics principles, particularly Bernoulli's equation for buoyancy. The drag depends on the object's surface area, shape, and the fluid's properties, which can complicate precise calculations, especially at varying depths. Given the dimensions provided, the object has a surface area of 750 cm² and is submerged at 20 meters. Accurate hand calculations may be challenging, and experimentation could yield better insights into the object's ascent speed and time to surface. Ultimately, understanding the drag force and buoyancy will be crucial for determining the object's behavior underwater.
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hi, newbie needs a little help...what is the formula and could someone please take the time to explain in detail how to compute the elements in the formula for the following task.

a submerged styrofoam rectangle with size H 100cm x L 15cm x W 50 cm. the object is submerged at 20 meters (60ft) underwater. it will be rising upward with the top side (750cm^2 area )
based on formula for drag, i need to calculate how long it will take to surface at the top, and what is its speed.

big thank you in advance...
 
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There really no hand calculation for this. You can define buoyancy force using Bernoulli's equation however the drag is rather difficult. It relies on the surface and geometry of the block which can change significantly depending on the depth its rising from. My suggestion is just to guesstimate with experimenting.
 
surface of the rectangular block is styrofoam, coated with thin fibreglass film, so it is 100% smooth. shape is defined in the initial text.
10x
 

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