Q. 5

# The free surface of a liquid resting in an inertial frame is horizontal. Does the normal to the free surface pass through the center of the earth? Think separately if the liquid is (a) at the equator (b) at a pole (c) somewhere else.

Here, we consider three different cases and discuss the direction of the net force on a liquid due to earth's gravity and rotation.

(a)At the Equator: Here, the force of gravity passes through center of the earth and the centrifugal force, which is the force due to rotation of the earth, is pointing vertically opposite to gravity but less in magnitude. Hence, normal to the free surface passes through the surface.

(b)At the Pole: Here, the centrifugal forces decrease to zero as the distance from the rotation axis is zero. Hence, only gravitational force acts on the liquid and the normal passes through the center of the earth.

(c) Somewhere else: In this situation, the centrifugal force will make some angle and hence the net force will not pass through the center.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos  Fluid Statics67 mins  Pseudo Force52 mins  Inelastic collisions in 1 D44 mins  A Lecture on Head-on Collision49 mins  NLM HCV Objective | Interactive Quiz63 mins  Questions Based on Equilibrium of a particle37 mins  Motion in 1 D38 mins  Newton Laws of Motion (Lecture 7)45 mins  Challenging Quiz on Newton Laws of Motion Part 364 mins  Moment of Inertia | Understanding the basics51 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation view all courses 