11- Biomechanical Movement

Question 1

Newtons three laws of linear motion applied to sporting movements

Answer 1

Newton‘s first law of inertia: ‘ everybody continues in its state of rest on motion in a straight line, unless compelled to change that state by external forces exerted upon it’. Newton‘s first law of inertia states that a force is required to change the state of motion. In a penalty, the ball (body) will remain on the spot (state of rest) unless it is kicked by the player an external force is acted on it)

-Newton‘s second law of acceleration: ‘ The rate of momentum of a body (or the acceleration for a body of constant mass) is proportional to the force causing it and the change that takes place in the direction in which the force acts’. Newton‘s second law of acceleration states that the magnitude (size) and direction of the force determines the magnitude and direction of the acceleration

         Force= mass x acceleration (F = ma))

When the player kicks (force) the ball during the game, the acceleration of the ball (rate of change of momentum) is proportional to the size of the force so the harder the ball is kicked the further and faster it will go

-newtons third law of action/reaction: ‘to every action force there is an equal and opposite reaction force’. Newton‘s third law of action/reaction states that for every action force there is an equal and opposite reaction force. When a footballer jumps up (action) to win a header, a forces exerted on the ground in order to gain height. At the same time the ground exerts an upward force (equal and opposite reaction) upon the player

Question 2

Definitions, equations and units of vectors and scalars

Answer 2

A scaler quantity is represented when measurements are described only in terms of size or magnitude for example mass, distance, speed, volume, power, volume.

A vector quantity is represented when measurements are described in terms of magnitude (size) and direction, for example weight, acceleration, displacement, velocity and momentum

Question 3

Definitions, equations and units of measurement for scalers and vectors

Answer 3

-Measurements of linear motion:
Mass (Kg)
-definition:
Mass is the quantity of matter the body possesses

• distance (m)
• is the path a body tight as it moves from the starting to finishing position
• speed (m/s)
• is a measurement of the body’s movement per unit of time, with no reference to direction
• speed= distance covered (m)/time taken (S)
• weight (Newton’s (N))
• is the gravitational force exerted on an object
• weight= mass (kg)x gravitational field strength (N/Kg)
• displacement (m)
• is the shortest route in a straight line between the starting and finishing position
• velocity (m/s)
• is the rate of change of displacement
• velocity= displacement (m)/ time taken (s)
• acceleration (m/s2) metres per second squared
• is the rate of change of velocity
• acceleration=change in velocity (m/s)/ time taken
• Momentum (kg m/s)
• is the product of the mass and velocity of an object
• momentum= mass (kg) x velocity (m/s)

Question 4

Theee classes of lever and examples of their use in the body during physical activity and sport

Answer 4

There are three classes of lever: first second and third. The classification of each depends on the positions of the fulcrum, resistance and effort in relation to each other.

-First class leavers (fulcrum)
Here, the fulcrum lies between the effort and resistance. There are two examples of this type of lever in the body: the movement of the head and neck during flexion and extension, and extension of the elbow

-second class lever (resistance)
In second class leavers, the resistance lies between the fulcrum and the effort. There are only one example of this type of lever in the body – planter flexion of the ankle

-third class lever (effort)
Third class levers can be found in all of the other joints of the body. The effort lies between the fulcrum and the resistance

Question 5

Mechanical advantage and disadvantage of each class of lever

Answer 5

-Class of lever:
Second

• advantages: can generate much larger forces, can lift the whole body weight with little effort
• disadvantages: slow, with a limited range of movement

-class of lever
First and third

• advantages: there is a large range of movement, any resistance can be moved quickly
• disadvantage: cannot apply much force to move an object

-third class lever is always have a mechanical disadvantage however they are able to increase the speed at the end of the lever arm

Question 6

First class leavers: mechanical advantage and disadvantage

Answer 6

+ If the Falcon is closer to the load, then a small amount of effort will result in more powerful movements of the load
-if the fulcrum is closer to the effort, more effort is needed to move the load, but it can be moved at a higher speed