TOPIC 5 - Lesson 1: Biomechanical Movement - Newtons 3 Laws

Question 1

What is linear motion?

Answer 1

• Motion in a straight or curved line, with all body parts moving the same distance at the same speed in the same direction.

Question 2

What is inertia?

Answer 2

• The resistance an object has to a change its state of motion.

Question 3

What is Newton’s first law of inertia?

Answer 3

• States that a force is required to change the state of motion.
• Example: Penalty - the ball will remain on the spot unless it is kicked by the player (an external force is exerted upon it)

Question 4

What is Newton’s second law of acceleration?

Answer 4

• The magnitude and direction of the force determines the magnitude and direction of the acceleration.
• Example: Sprint (start) - athlete will have to apply a large force internally with their gluteals, quads and gastrocnemius as they drive forward.

Question 5

What is the calculation for force?

Answer 5

• Force = mass x acceleration (F = ma)

Question 6

What is Newton’s third law of motion?

Answer 6

• States that for every action there is an equal and opposite reaction.
• Example: Header - force is exerted on the ground in order to gain height, same time ground exerts an upward force upon the player.

Question 7

What is ground reaction force?

Answer 7

• The equal and opposite force exerted on a performer who applies muscular force on the ground.

Question 8

What is a scalar quantity?

Answer 8

• A quantity which only has magnitude.
• Examples: speed, distance, time

Question 9

What is speed - how is it calculated?

Answer 9

• The rate of change of position.
• Speed (m/s) = distance covered (m) / time taken (s)

Question 10

What is distance?

Answer 10

• The total length of the path covered from start to finish (A - B)

Question 11

Define stability.

Answer 11

• The body’s resistance to movement.
• Can be affected by the COG, BOS, LOG and mass

Question 12

Define balance.

Answer 12

• The ability to maintain the LOG of a body within the BOS with minimal postural sway.

Question 13

What is the centre of mass?

Answer 13

• The point at which the body’s mass is equally distributed or balanced in all directions.

Question 14

What is the line of gravtiy?

Answer 14

• The line extending vertically downwards from the centre of mass.
• Helps determine balance.

Question 15

What is the base of support?

Answer 15

• The area beneath and between the points of contact an object or person has with the ground
• The greater the number of contact points, the larger the base of support and the more stability a person has.
• When the COG moves outside the BOS, the person becomes unstable and risks falling over.

Question 16

What are the factors affecting stability?

Answer 16

• The height of the centre of mass: lowering the centre of mass will increase stability
• Position of the line of gravity: should be central over the base of support to increase stability.
• Base of support: the more contact points, the larger the base of support becomes and the more stable they become.
• Mass of the performer: often the greater the mass, the more stability there is because of increased inertia.