Q1 of 24 Page 72

A tall cylinder is filled with viscous oil. A round pebble is dropped from the top with zero initial velocity. From the plot shown in Fig. 10.1, indicate the one that represents the velocity (v) of the pebble as a function of time (t).

When a pebble is dropped in a fluid, a variable force called viscous force acts on it. This force increases the velocity of the pebble until it becomes constant. This constant velocity is called the critical velocity. Since, the force is variable, acceleration is variable and so v-t graph is curved and not a straight line to which critical velocity vc is an asymptote.

More from this chapter

All 24 →
2

Which of the following diagrams (Fig. 10.2) does not represent a streamline flow?

 3

Along a streamline

 4

An ideal fluid flows through a pipe of circular cross-section made of two sections with diameters 2.5 cm and 3.75 cm. The ratio of the velocities in the two pipes is

 5

The angle of contact at the interface of water-glass is 0°, Ethyl alcohol-glass is 0°, Mercury-glass is 140° and Methyliodideglass is 30°. A glass capillary is put in a trough containing one of these four liquids. It is observed that the meniscus is convex. The liquid in the trough is