Two small spherical metal balls, having equal masses, are made from materials of densities \(\rho_1\) and \(\rho_2\) such that ${\rho }_1=8{\rho }_2$ and having radii of \(1\) mm and \(2\) mm, respectively. They are made to fall vertically (from rest) in a viscous medium whose coefficient of viscosity equals $\eta$ and whose density is \(0.1\)${\rho }_2$. The ratio of their terminal velocities would be:
1. $\frac{79}{72}$

2. $\frac{19}{36}$

3. $\frac{39}{72}$

4. $\frac{79}{36}$

A small spherical solid ball is dropped in a viscous liquid. Its journey in the liquid is best described in the figure by:
                        

A small tiny water droplet is falling towards earth at a uniform speed of 1 cm/s. When 27 such identical droplets combine together to form a bigger drop, then with what uniform velocity will this bigger drop fall?

1. 27 cm/s

2. 9 cm/s

3. 3 cm/s

4. 81 cm/s

If a small drop of water falls from rest through a large height h in air, then the final velocity is:

An iron sphere is dropped into a viscous liquid. Which of the following represents its acceleration (a) versus time (t) graph?

1.		2.
3.		4.

A small sphere of radius \(r\) falls from rest in a viscous liquid. As a result, heat is produced due to the viscous force. The rate of production of heat when the sphere attains its terminal velocity is proportional to:
1. \(r^3\)
2. \(r^2\)
3. \(r^5\)
4. \(r^4\)