An aluminum sphere (specific gravity = 2.70) falling through water reaches a terminal speed of 8.36 cm/s. what is the terminal speed of an air bubble of the same radius rising through water? assume viscous drag in both cases and ignore the possibility of changes in size or shape of the air bubble; density of air at 20°c is 1.20 kg/m3 and that of water is 998.21 kg/m3.

4.91 cm/s

Explanation:

Given

Specific Gravity

During falling velocity is

Let during rising velocity be

Density of air

density of water

For Aluminium sphere

-------1

For second case

----2

Divide 1 and 2 we get

Drag force is given by

therefore

because

Taking   common

see earlier answer

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.