Biomachanics

Question 1

What is Newtons fist law of inertia

Answer 1

A force is required to change the state of motion

For example in a penalty the ball will remain on the spot unless it is kicked by the player

Question 2

What is Newton’s second law of acceleration

Answer 2

The magnitude (size) and direction of the force determines the magnitude and direction of the acceleration

For example when a player kicks the ball during the game, the acceleration of the ball is proportional to the size of the force. So the harder the ball is kicked, the further and faster it will go in the direction in which the force has been applied

Question 3

Newton’s third law of motion

Answer 3

For every action there is an equal and opposite reaction

For example when a footballer jumps to win a header, force is exerted on the ground to gain height, at the same time the ground exerts an upward force (equal and opposite) upon the player

Question 4

What are scalar quantities

Answer 4

When measurements are described in terms of their size and magnitude not direction

E.g speed, distance and mass

Question 5

What is the formula for speed

Answer 5

Speed (m/s)= distance (m) / time (s)

Question 6

What is the centre of mass

Answer 6

This is the point of balance

Question 7

What is a Line of gravity

Answer 7

This is the line extending vertically downwards from the centre of mass

Question 8

What are factors affecting stability

Answer 8

The height of the centre of mass - lowering the centre of mass will increase stability

Position of the line of gravity - should be in the centre of the base of support to increase stability

Area of support base - the larger the base of support the more stable they become

Mass of the performer - often the greater the mass, the more stability there is because of increased inertia

Question 9

What is a first class lever and example

Answer 9

Fulcrum is in the middle between effort and load

E.g throw in, extension at the elbow

Question 10

What is a second class lever and example

Answer 10

The load lies between the fulcrum and the effort

E.g calf raises, plantar flexion at the ankle

Question 11

What is a third class lever system and example

Answer 11

Effort lies between the fulcrum and the load

Everything else apart from throw in and calf raises

Question 12

What is the fulcrum

Answer 12

The point about which the lever rotates

Question 13

Load

Answer 13

The weight to be moved by the lever system

Question 14

What is the effort

Answer 14

The force applied by the user (muscle) of the lever system

Question 15

What is the effort/force arm

Answer 15

The length of the line between where the fulcrum and effort are labelled

Question 16

What is the load arm

Answer 16

The length of the line between the fulcrum and load

Question 17

What is a mechanical advantage

Answer 17

Where the effort arm is longer than the load arm

Question 18

What is Mechanical disadvantage

Answer 18

Where the load arm is longer than the effort arm

Question 19

What is the mechanical advantage at a second class lever

Answer 19

Effort arm is always longer than the load arm

Can generate much larger forces
Has to lift the whole body weight
Can lift large loads over small distances
However difficult to generate speed

Question 20

2

Answer 21

.

Question 22

Mechanical disadvantage at third class lever

Answer 22

Load arm is always longer than the effort arm

Cannot apply much force to move an object
Large range of movement
Can’t move heavy loads
But can do it faster