Law of motion,Force,Newton's law of motion, linear momentum, impulse ,Friction

Force

Force is a push or pull which can change the position of a body as required. It is a vector quantity following all the rules of vector. Forces are of two types

1. Balanced Forces If there are many forces acting on a body, but resultant of all of them is zero, then the forces are called balanced forces.

2. Unbalanced Forces If the resultant of all the forces is not zero, then the forces are called unbalanced forces.

Newton's Law of Motion

There are three laws of motion

First Law

"Everybody remains in its state of rest or state of motion, until an external force is applied on it." This law is also known as law of Inertia Inertia is a property by virtue of which, a body tries to retain its state. Inertia are of two types

1. Inertia of Rest If a body is in rest, then it will remain in rest until an external force is applied on it.

2. Inertia of Motion If a body is in motion, then it will remain in motion until an external force is applied on it.

There are some examples of inertia in everyday life.

(i) A glass is broken into pieces when a stone strikes on it, but when a high speed bullet hits the glass it makes a clean hole.

(ii) The persons sitting in the bus falls backward when bus starts to move suddenly. (iii) An athlete runs very fast before taking high jump.

(iv) A man getting down of a moving bus falls forward.

Second Law

"The force applied on a body is equal to the product of mass of the body and the acceleration produced in it.

F = ma

and also the rate of change of linear momentum (p = mu) of a body is proportional to force applied in direction of force .

Third Law

"Every action have equal and opposite reaction." Action and reaction always act on the different bodies.

Linear Momentum

The product of mass and velocity of a body is called linear momentum. It is represented by p. its unit is kg-m/s. It is a vector quantity. p = mv

Impulse

If a force acts on a body for a very short time At, then the product of force and time is called the impulse.

Impulse = Change in momentum or Impulse

Friction

When a body slides (or has sliding tendency) or rolls over another body or on a surface, then a force opposing the motion acts between those surfaces of the body which are in contact, this force is called friction. Two basic types of friction is kinetic friction and static friction.

What are life process?

WHAT ARE LIFE PROCESSES? The maintenance functions of living organisms must go on even when they are not doing anything particular. Even when we are just sitting in class even if we are just asleep, this maintenance job has to go on The processes which together perform this maintenance job an We processes . Since these maintenance processes are needed to prevent damage and break-down energy is needed for them. This energy comes from outside the body of the mdhadual organism. So there must be a process to transfer a source of energy from outside the body of the organism which we call food, to the inside, a process we commonly call nutrition If the body size of the organisins is to grow, additional raw material wit also be needed from outside. Since life on earth depends on carbon- based molecules most of these food sources are also carbon-based Depending on the complexity of these carbon sources, different organisms can then use different kinds of nutritional processes The outside sourc...

Nutrition in human being?

Nutrition in Human Beings The alimentary canal is basically a long tube extending from the mouth to the anus. we can see that the tube has different parts. Various regions are specialised to perform different functions. What happens to the food once it enters our body? We shall discuss this process here. We eat various types of food which has to pass through the same digestive tract, Naturally the food has to be processed to generate particles which are small and of the same texture. This is achieved by crushing the food with our teeth, Since the lining of the canal is soft, the food is also wetted to make its passage smooth. When we eat something we like, our mouth waters. This is actually not only water..but a fluid called saliva secreted by the salivary glands. Another aspect of the food we ingest is its complex nature. If it is to be absorbed from the alimentary canal, it has to be broken into smaller molecules. This is done with the help of biological catalysts called enzyme...

Adaptation in lion & adaptation in deer

A large area of land covered mainly with trees and plants is called alaust And a large area of grass covered land used for grazing is called grassland There are few trees or places for animals to hide gland habitats. Due to this speal is important for the animals which live in grassland habitats (so they can nits away from their enemies) For most common purposes, however, the wrous forest and and are used in the same sense. The forest (or grassland) is a habitat Many animals such as lon som elephants deer, en live in forest habitats. There are many features of a lion, a deck, other animals and plant which help them to survive in the forest habitat. The adaptations in lion and deer to the forest habitat are described below. Adaptation of lion The lion is a camivorous animal which eats only the meat (or flesh) of oder animals. The lion lives in a forest habitat The adapted to the forest habitat in the following ways: 1.The lion is a strong, fast and agile animal which can hunt and ...

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