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Physical Education Class 12th ~ UNIT - 8 Biomechanics and Sports



                    Biomechanics and Sports


Meaning of Biomechanics:
Bio + Mechanics
Bio  Living organism
Mechanics  Branch of Physical scince which deals with
force acting on a body in static condition or in moving condition.
Biomechanics: is the study of forces & their effects on human

being is moving or in static condition.


Q.1. What is Biomechanics? How it helps in the field of sports &
games.
Ans. Bio :  living organism
Mechanics : Branch of Physics. Which deals with effect of force on the object
BioMechanics is branch of Sicience which deals with effect of forces acting on a living of organism in moving condition or in Stationary conditon. Biomachanics helps in the field of sports in the following way.
1. Imporvement of Technique: Biomechanics helps to improve technique. It determine how the technique should be execute to get best result.

Example: Shifting from orthodox to discoput Technique is shotput
2. Improvement of Equipment: If helps to lmprove equipment According to nature & safety of the game for example in increase in thickness of mat for high jump
3. Improvement in Training method: It helps to develop new Traning method to get better result. for example Devlopment of Isotonic mehtod to devlop strength.
4. Devlopment of Skill: It helps to devlop skill of the sports. Example: Devlopment in the skill of fielding in cricket.


Q.2 What is power?

Ans. The Rate of doing work or using energy is called power.



Q.3. Discuss the Abduction, Adduction, flexion & extension with suitable examples in detail? Name the Movements which occours in legpress exercise? 
Ans. (1) Abduction: It is that Movement in which
 moving body part move away from the midline of body
 It always occours on frontal plane & segittal axis.
Example: Moving of hand in sidewise disection i.e. hand going away from body.
(2) Adduction: It is that Movement in Which
 Moving part coming towards the midline of body
 It alway occour at frontal plane segittal axis
Example to back his hand to Attention position from the hands opening sides stage
(3) Flexion: It is that movement
 In which the joint on which the movement occous. There will be decrease in the angle between the bone of that joint
 It always occours at segittal plane & frontal axis
Example: Bending of Elbow and bending off knee

(4) Extension: It is that movement
 In which the angle between the bone of that joint on which movement is occoured will increase.
 It always occours at segital plane & frontal axis
Example: Straighting of elbow from bending position
– Straighting of knee from bending position in leg press
exercise
– In leg press exercise flexion of knee joint and extension of knee joint take place.


Q.4. What are the newton’s law of mation? Explain the Application of IInd law of Motion (any two applications) 
Ans. Ist Law of Motion (Law of Inertia): any object will be remains in its position until or unless any external force is applied on it.
IInd law of motion (Low of Acceleration): The rate of change of acceleation is directly proportional to the force applied on the object and Inversly proportional to the mass of the object.
IIIrd law of motion (low of action and Reaction): There will be equal & opposite reaction to each & every action.



Application of IInd low of motion
Example 1: According to IInd law motion if we want to produce acceleration in football Then a large force will be required to put on the ball. In the same ratio to which force is applied on the ball will be accelerate.

Example 2: Landing of high jump initally done on the sand but with the time change now landing of high jump will be done on the mats as according to IInd law when rate of change of momentum will be done in large time period less force will be produce which will helpful to avoid injury.
So according to IInd law landing on the mats is more favourable for high jumper to avoid injury.


Friction & Sports.
Friction: is a force that devlops when the surfaces of two objects comes in contract to each other & there will be relative motion between these objects or tends to do relative motion between these two object. Friction force alway act in opporite direction to the movement.


Q.5. What is Friction? Discuss various types of Friction.
Ans. Friction is the force that combats relative motion between the two surfaces that comes in contact. Friction always acts in the opposite direction of the applied force. Type of frictions:
Static friction: The opposite force that comes into play when one body is actually not moving over the surface of another body. Dynamic friction are two types.
Rolling friction: The oppsing force that comes into play when body is actually rolling over the surface of another body. For example, hockey/cricket ball is hit Force direction
Speed direction
Friction
Rolling friction

Sliding Friction: The opposite force that comes into play when one body is actually slide over the surface of other body for example sliding on the field of cricket by a fielder.


Q.6 Define work?
Ans. Work refers to an activity involving a force and the Movement in the direction of force. It can also be defined as “the work done by a constant force as the product of force and the distance moved in the direction of the force”.



Q.7 Explain Gravity?
Ans. Gravity is the force of attraction exerted by the earth towards its centre on a body or an object.

Q.8 Define trajectory?
Ans. The flight path followed by a projectile is called it’s trajectory.Ex. Throwing a ball into air.

Q.9 Explain one of the most important difference between the Mechanical analysis of walking and running?
Ans. In running a time comes when both the feet are off the ground which is called float phase, while in walking one foot is always in contact with the ground.

Q.10 What is air resistance?
Ans. Resistance is a force, which created by the contact is between the two surfaces. When a projectile moves through the air, the force applied by the air that opposes the motion of the

projectile is called air resistance.


Q.5 Mr. Vinay is a physical education teacher in a govt. school and he was a rencwned national level long jumper during his teenage. Mahesh is also a long jumper & his landing is improper. So he
lost his position. Mahesh went to Mr. Vinay to seek help Mr. Vinay gave him proper scientific technique tip to follow correct body posture while landing & also motivated to utilize the same jump
consistant practice. After the one year of training mahesh won gold medal in the Inter Zonal Athletic Meet.
I. What was the problem facing by Mahesh body?
II. State the qualities of Mr. Vinay as a coach?
III. Explain the role of coach in the life of a sports man?


Ans.(i) He was facing problem in landing technique of Long Jump/ Mahesh was facing the problem of improper Landing in his long jump event so he didn’t win any medal in the athletic meet.
(ii) Mr. Vinay has following qualities.
1. Good motivate, 
2, Dutifulness, 
3. Knowledge of scientific techniques or masteng in skill, 
4. Helping attitude, 
5. Good co-cordination.

(iii) As a coach he can play in two different areas :-
i. Information feed back, implimentation in respective field of skill.

ii. Suggest, refer, engage with field experts.


Q.1 What is projectile ? Explain the factors affecting projectile trajectory

Or
Write in brief that how angle of projection, height of releas speed of release, gravity and air resistance affect projectile trajectory.
Ans. An object thrown into the space either horizontally or an acute angle under the action of gravity is called a projectile. There are force which act on a projectile-gravitational force and air two resistance. Air resistance of an object varies greatly and it depends on the object’s particular shape and the atmoshperic conditions in which the object is released.
Trajectile - The path followed by a projectile.
The factor affecting Projectile Trajectory are mentioned below.
1. Angle of projection:- An object which is projected at different angles covers different distance. When it is projected or released
at angle of 25O, making it a parabolic path and coves lesser distance. When it is released at angle of 42O & 45O, makes a parabolic path and covers. Maximum distance. So thendistance covered by an
object (Shot Put, Hammer, Javelin,Discus etc. depends on the angle of release of projectile.



2. Projection height relevant to the landing surface:-
If the projection height and landing surface are equal the thing should be release/thrown at an angle of 42O to 45O it cover maximum distance. If the level of landing surface is more than projection height the angle shall be increased i.e. should be more than 45O.So thing are cover a maximum distance. If the level of Landing surface is less than projection height the angle of projection should be decreased. I.e. should be less
the 450. The things are cover maximum distance. So the distance of horizontal depends upon the relevancy of projection height and landing surface.
3. Initial velocity:- The distance covered by on object depends on the initial velocity of the projectile. If the initial velocity is more, the object
covers maximum distance. And if he initial velocity is less the object covers less distance.
42 to 45 0 0 Trajectory Initial Horizontal velocity

4. Gravity:- It is the force of attraction exerted by the earth towards the object’s. A Leaner object, if rojected will have longer elivation in companison to a light weight object with the same force. Gravity affects a projectile as it decreases the height of the force of gravity acts on the object to stop its upward movement and pulls it back tearth. Limiting vertical component of the projectile.
5. Air Resistance:- When a projectile moves through the air, it is slow down by air resistance,
Air resistance decrease the h o r i z o n t a  component of projectile. The effect of air resistance is very small but it increase the horizontel component of air resistance acting on a projectile mass surface of the object. Following factors - Surface of the object volume, mass & speed related to the amount of air resistance of a projectile.




Physical Education Class 12th

UNIT - 1 Planning in Sports


UNIT - 6 Test & Measurement in Sports

UNIT - 7 Physiology and Injuries in Sports

UNIT - 8 Biomechanics and Sports

UNIT - 9 Psychology and Sports

UNIT - 10 Training In Sports





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