Gravitation

Tutormate > CBSE Syllabus-Class 9th Physics > Gravitation

04 Centre of Mass

CENTRE OF MASS

The centre of mass of a body may be defined as the point at which the whole mass of the body may be assumed to be concentrated.

CENTRE OF GRAVITY

The centre of gravity of a body is a point at which the resultant of all the parallel forces due to gravity experienced by various particles of the body acts or at which whole weight of the body acts.

CENTRIPETAL ACCELERATION OF THE MOON

If the moon is revolving with speed v in a circular orbit of radius r, then acceleration acting on it along the radius and towards the centre of its orbit is

ac = \frac{v^{2}}{r}

Equations of Motion for Freely Falling Bodies:

General equations of motion		Equations of motion for freely falling bodies
1. v = u + at	$\to$	v = u + gt
2. $s = ut + \frac{1}{2} {at}^{2}$	$\to$	$h = ut + \frac{1}{2} {gt}^{2}$
3. $v^{2} = u^{2} + 2 as$	$\to$	$v^{2} = u^{2} + 2 gh$