What is the formula for velocity and time taken of object falling in water

[malek340]

What is the formula of the velocity and time taken of an object faling in water? I have the mass, the density, the volume of the object and the height distance of the falling object. I know that the drag force is included in the formula but i have idea how to calculate it. So anyone knows this?

 

[arildno]

Well, Stoke's law of resistance is the simplest approximation, and in many cases good enough.
In full generality, the problem does not have any simple answer.
Look at the subsection concerning Stokes drag:
http://en.wikipedia.org/wiki/Drag_(physics)

 

[Rorkster2]

i read about how a kid about 15 years old just cracked (within a month or 2 ago) the math behind objects falling with air resistance. id imagine its related to that although it would need to be tweeked, and its doubtful that's been done yet

 

[sophiecentaur]

I seem to remember a story that Stoke managed to get his formula whilst sitting a Physics exam in which the Professors had put the 'unanswerable' question of a sphere falling through a fluid, just to give students a hard time. (Ah, those were the days!)
His correct answer caused quite a stir.

 

[PJC01]

The formula for velocity and time taken of an object falling in water can be determined using the equations of motion. The velocity (v) of the object can be calculated using the equation v = u + at, where u is the initial velocity (which is usually zero for objects falling from rest) and a is the acceleration due to gravity, which is approximately 9.8 m/s^2 for objects falling in water.

The time taken (t) for the object to reach the water's surface can be calculated using the equation t = √(2h/g), where h is the height distance of the falling object and g is the acceleration due to gravity.

To calculate the drag force, we need to use the equation Fd = ½ρAv^2C, where ρ is the density of the water, A is the cross-sectional area of the object, v is the velocity of the object, and C is the drag coefficient which depends on the shape and size of the object.

Using this equation, we can calculate the drag force and then use it in the equation of motion to determine the final velocity and time taken of the object falling in water.

It is important to note that the drag force will also depend on other factors such as the viscosity of the water and the surface roughness of the object. These factors can be included in the calculation by adjusting the drag coefficient.

I hope this helps to answer your question. If you need further assistance with the calculations, I recommend consulting a physics textbook or seeking help from a qualified scientist or tutor.