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.
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.
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 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:
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.
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 is Friction?
Momentum is the motion contained in a body. Quantity of motion possessed by a body depends upon both of its mass and velocity. So the product of mass and velocity is the measure of the momentum,
Newton's First Law of Motion
According to Netwon's first law of motion,
The dimension of a physical quantity is defined as the power to which the fundamental quantities are raised to express the physical quantity. The dimension of mass, length and time are represented as [M], [L] and [T] respectively. For example: