Vacancy for Driver in Sri Lanka

Vacancy for Driver in Sri Lanka

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Address; No 5,13th Lane,Col 03,

Colombo 03, Colombo

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Unceasing Process In Which The Balance Of The Body Is Lost And Regained.

While Walking, The Balance Of The Body Is Maintained By Moving Hands And Legs In

Opposite Directions.

Running

Running Is To Be Pushed Forwards By The Force That Is Exerted On The Ground By The

Feet. When Running, A Runner Exerts Some Force On The Ground And Consequently An

Equal And Opposite Force Acts On The Runner. The Runner Moves Forwards Because Of

The Reactive Force That Is Generated. (Figure 3.6)

34 For Free Distribution. 35

Figure 3.6 Figure 3.7

At The Start Of A 100-Metre Race, A Sprinter Remains At Rest On The Starting Block. 

He

Exerts Some Force On The Block Using His Feet. As The Reactive Force Generated By The

Block In Response To The Athletes Force, Acts Back On Him, He Is Pushed Forwards. If

That Reactive Force Does Not Act On Him, He Remains At Rest On The Block. (Figure 3.7)

For Extra Knowledge

Apply The Second Law Of Newton That You Learnt In Science To The

Example Given Above.

“The Acceleration Of A Body Is Directly Proportional To The Unbalanced

Force Acting On It, While It Is Inversely Proportional To Its Mass.''

According To This Law, Acceleration Of An Object Or An Athlete Can Be Increased By

Increasing The Force That Acts Upon That Object Or The Athlete (A Higher Rate Of Velocity

Change).

The Acceleration Produced When A Sprinter Of A 100-Metre Race Takes Off At Starting

Block Is Directly Proportional To The Force That He Exerts On The Block. If The Force He

Exerts On The Block Is Greater, The Acceleration Of Taking Off The Block Is Greater, Too.

34 For Free Distribution. 35

3.8 Figure

Jumping And Throwing

Releasing An Object To The Air By Throwing Or Shooting Forward, Is Called A Projection

And The Object That Is Projected Is Called The Projectile.

In Sports And In Physical Education Activities, There Are Various Events In Which

Objects Are Thrown Forwards.

Eg: Javelin, Shot Put, Discus

Moreover, Various Pieces Of Sports Equipment Are Thrown Forwards Using Various

Techniques.

Eg: Hitting The Ball, Kicking The Ball

In Events Like Long Jump, High Jump, Triple Jump And Hurdles, The Body Of The Athlete

Becomes The Projectile.

For Extra Knowledge

The Centre Of Gravity Of A Piece Of Sports Equipment Or That Of An Athlete

That Is Taken-Off Into The Air Moves Along A Circular Path In The Air. This

Path Is Called The Trajectory.

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The Following Figure Shows The Path Of The Centre Of Gravity Of A Long-Jumper

From The Time He Takes Off Until He Lands.

Figure 3.9

A = Point Of Taking Off

B = Landing Point

A-B = Distance Of The Jump

H = Take-Off Height

Factors Affecting The Distance Or The Height Of The Jump Of

An Athlete

1. Velocity Of Take-Off

2. Angle Of Take-Off

3. Height Of Take-Off

The Height Or The Distance Of The Jump Determined On The Above Factors Cannot

Be Changed By The Movements That The Athlete Makes While He Is In The Air. In An

Event Like Long Jump, Such Movements Are Only Useful In Preparing The Body For A

Successful Landing. (Figure 3.10)

Figure 3.10