## Center of Mass

The center of mass (not to be confused with center to gravity) of a body is the point which behaves as if all the mass of the body is concentrated there. Thus, if a force acts at this point, the body will accelerate but will not rotate.

## Center of Gravity Definition, Equation and Calculation

The center of gravity (not to be confused with center of mass) of a body is a point where the weight of the body acts and total gravitational torque on the body is zero.

## Escape Velocity: Definition, Formula, Derivation

When an object is thrown vertically upwards, it reaches a certain height and comes back to the earth. But when it is given greater initial velocity, it reaches greater height before coming back.

## Understanding Blood Groups & Its Inheritance

Blood caries many chemicals, which have various functions. One group of chemicals is called antigens, which can stimulate the production of antibodies. Based on the presence or absence of blood antigens and antibodies, four groups A, B, AB and O are recognized in human body. Antigens are the proteins on the surface of red blood cells. Blood of one group contains antibodies in the plasma that reacts against the antigen on the cells of other groups.

## Factors Affecting Climate Change

Climate is the average atmospheric condition of a particular place. It is different from weather because weather changes continuously but climate changes every 30 to 35 years. For example: If it rains continuously in a place every day, the climate there is monsoon. The pattern of weather of a place is known as the climate of a place.

## Birth and Death Of Stars

A star is a self-luminous celestial body which converts nuclear energy into heat, light and other radiant energies. There are millions of stars in the universe. They are not uniformly distributed but are collected together in a group called galaxy. The Sun is also a star which is the member of the Milky Way Galaxy and it is the nearest star from the Earth.

## Measurement and Units of Measurement in Physics

Measurement is a process of detecting an unknown physical quantity by using standard quantity. For example: Take a book and use ruler (scale) to find its length. Suppose the length was 20 cm. You underwent through a process called Measurement where:

## Law of Conservation of Energy and Potential to Kinetic Energy Conversion

According to law of conservation of energy, Energy of an isolated system is constant. It can neither be created nor be destroyed but it can be transformed from one type to another. For example, when an object falls on the ground from a certain height, its kinetic energy is converted into other forms of energy such as sound energy, heat energy, light energy, etc.

## Kinetic Energy and Work-Energy Theorem

Kinetic Energy The energy possessed by a body due to its motion is called kinetic energy. So from the definition, it is known that kinetic energy increases with increase in speed of the particle. Few examples of bodies possessing kinetic energy are a moving bus, moving water in a river, a moving bullet, etc.

## What are different types of Friction?

What is Friction?