# Spherical Polar co-ordinates

The spherical polar coordinates represent the coordinates of points on the surface of a sphere in a co-variant form. The coordinates of the point P in this system is represented by the radial vector r which is the distance from the origin to the point, the polar or

# Frame of reference and Rectangular Cartesian co-ordinate system

The motion of different bodies can be conveniently described if we imagine co-ordinate system attached to a rigid body and the positions of different bodies in space can be described w.r.t. it, then such co-ordinate system is called frame of reference.

# Center of mass : Dynamics of system of particles

## What is center of mass?

Let us consider a body consisting of large number of particles whose mass is equal to the total mass of all the particles. When such a body is having translational motion then displacement is produced in each and every particle.
The center of mass of a body is defined as the point where whole mass of the system can be supposed to be concentrated.

# External and internal forces (Dynamics of system of particles)

This lesson is about External and internal forces (Dynamics of system of particles) . This chapter comes under subject Mechanics and is for B.Sc. Physics students.   While studying Newton’s laws of motion most of the time we have considered objects (for example planets, projectiles etc..) to be point particles rather then extended bodies. We did … Continue reading External and internal forces (Dynamics of system of particles) »