Biomechanics

Question 1

What is Motion?

Answer 1

Motion is defined as the change of location or position of an object with respect to time

Question 2

What is Linear motion?

Answer 2

Linear motion is the movement of an objects Centre of mass in a straight or curved line

Question 3

How is linear motion created?

Answer 3

It is created through the application of a force acting through the center of mass

Question 4

How do you calculate Speed?

Answer 4

Speed = distance/time (s =d/t)

Question 5

How do you calculate Velocity?

Answer 5

Velocity = displacement/time or distance/time (m/s)

Question 5

How do you calculate Acceleration?

Answer 5

Acceleration = (final velocity – initial velocity)/time taken (m/s²)

Question 6

How do you calculate Angular momentum

Answer 6

Angular momentum = moment of inertia x angular velocity

Question 7

Define Speed

Answer 7

Speed is defined as the rate at which a body moves from one location to another

Question 8

Define velocity

Answer 8

Velocity is defined as the rate at which an object changes its position

Question 9

Define acceleration

Answer 9

Acceleration is defined as the rate at which velocity changes with respect to time

Question 10

Define angular motion

Answer 10

Angular motion is the rotation of an object about a fixed axis

Question 11

What does the moment of inertia depend upon?

Answer 11

The mass of the object, the more mass the larger the moment of inertia
The distribution of the mass away from the axis of rotation, the further away the mass is from axis of rotation the greater the moment of inertia.

Question 12

What is the moment of inertia?

Answer 12

The moment of inertia is the resistance of an object to rotate and is rotational equivalent of mass

Question 13

What is angular momentum equal to?

Answer 13

Angular momentum is equal to the product of the moment of inertia of a body & its angular velocity.

Question 14

what factors effect how far an object will travel in throwing events?

Answer 14

Initial velocity
The height of release
The angle of release
Angle of attack
Drag
Applying some spin
Air resistance
Gravity - gravitational forces affect the vertical motion of an object and because gravity affects heavier objects more, lighter ones will usually travel further.

Question 15

What does initial velocity depend on in throwing events?

Answer 15

The speed of the run up, which is especially important for javelin throwing as the velocity the thrower is travelling upon the javelin being released is added to the forces provided by the rest of the body.
The force applied to the object (more specifically the impulse – see later). Therefore, throwers with more explosive strength are likely to be able to transfer more force from their muscular contractions.

Question 16

How does the height of release effect how far an object will travel in throwing events?

Answer 16

The more height at release the more horizontal distance, therefore taller athletes have advantage over short ones in throwing events.

Question 17

How does the angle of release effect how far an object will travel in throwing events?

Answer 17

The optimal angle of release is usually calculated to be 45° to maximize horizontal distance. However, in reality there are few objects that should be released at this angle. Balls struck from the floor may fit this recommendation but when objects are released higher than they will land a lower angle is recommended, approximately 43-44o for a hammer thrower). The optimum angle of release for a discuss is usually only about between 35 and 40o which is because of the Bernoulli effect.

Question 18

How does applying some spin effect how far an object will travel in throwing events?

Answer 18

Applying some spin to a discus can help to improve the distance thrown, as long as the angle of attack is correct. However, many novices do not apply forces through the CoM of a javelin and cause angular momentum so that the javelin turns over end-over-end. This spin can massively increase air resistance and the distance thrown.

Question 19

How does air resistance effect how far an object will travel in throwing events?

Answer 19

Air resistance – this has a negligible effect on most objects if thrown correctly. However, in discuss throwing if the ‘angle of attack’ is not correct then air resistance and drag can reduce the distance it travels.

Question 20

How does gravity effect how far an object will travel in throwing events?

Answer 20

Gravitational forces affect the vertical motion of an object and because gravity affects heavier objects more, lighter ones will usually travel further.

Question 21

What does the influence of air resistance depend on?

Answer 21

Object mass
Surface area
Projectile speed - generally the speed of release has the greatest influence on projectile range than angle/height of release
Influence of any motions of the projectile other than direction of flight, e.g. topspin, backspin, hooking, slicingo
Surface covering the projectile