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Importance of Physical Exercise according ot age and sex

Importance of Physical Exercise according ot age and sex According to Age: Physical education is applicable for people of all ages. But programmes of physical education differ likings and dislikings for different age-groups. Not only physical exercise but also food, likings and dislikings and physical abilities are different for different age-groups. For example, physical ability of children is not equal to that of adults.  So to develop the abilies exercise through games should be introduced accordingly. Frog jumps, touch and back, crow jump or recreational games are some physical activities that can improve physical ability of children. Selection of exercise and games for adolescent should be done systematically. Standing in a line, exercise of hands and legs, running with a ball, touch and play, etc. and games and physcial exercise can be used to develop physical abilities of children. Remember, children and adolescents should not participate in weight lifting exercise. It causes h

Friction is a necessary evil - give an argument in favor of it.

Friction is a necessary evil - give an argument in favor of it.

Friction is considered a necessary evil. We cannot do anything without the force of friction. If there was no friction, the motion of a body would not cease at all and continue perpetually. Friction has made it possible to write on paper with a pencil or a pen. We can walk as there is friction between our shoes and the ground. To make life and works easier we need friction. 

When an object moves or tends to move over another object, this resistance is known as friction. Friction is called a necessary evil on the ground that it is necessary in spite of having certain disadvantages.

To speak about the necessity of friction, what comes first is that the motion of a body would never cease but would continue perpetually if there were nothing to be friction. It plays a vital role in our practical life. It makes contracting buildings, houses, and bridges possible. We could not even fix a nail if there were no friction.

Friction has made it possible to write on paper with a pencil or a pen. We can walk as there is friction between our shoes and the ground. We can change the direction of motion of a car owing to friction. Using a parachute it is possible to descend safely to the ground by harnessing the air resistance. In spite of having so many advantages, we have to suffer a lot from friction.

Because of excess friction, the vehicles cannot move easily. Any device that has moving parts can wear out and tear due to friction. In any type of vehicle may be a car, boat, or airplane, extra fuel has to be spent to overcome the excess friction. Fuel energy is being wasted because of friction.

The advantages and disadvantages of friction clarity that friction is a necessary evil.

Friction slower the moving of an object; in order words, it hinders the movement of an object. Pulling or pushing would be very much faster and easier if there were nothing to be friction. We could reach our destinations much earlier if friction would not take place between the surfaces of the roads and those of the tyres of the vehicles. 

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