biomechanical principals

Question 1

define newtons 1st law of motion

Answer 1

law of inertia: an object will remain at rest until acted upon by a larger external force to overcome inertia

Question 2

give a sporting example of newtons 1st law

Answer 2

for a centre pass in netball the ball will reamin in the centre’s hands until she applies a large enough muscular force to the ball to pass it to a teamate,. the ball will continue to move at constant velocity in the direction thrown until caught by another player, when the velocity of the ball will increase.

Question 3

define newton’s second law of motion

Answer 3

law of acceleration: the bodys rate of change of momentum is proportional to the size of the force applied and acts in the direction of the force, the greater the force the greater the accelaration however mass remains constant

Question 4

what is the equation for force

Answer 4

force = mass x acceleration

Question 5

give a sporting example for netwons 2nd law

Answer 5

a netball goal shooter who has recieved the ball in a strong position close to the goal will only ned to impart relatively small amount of force in the direction of the net. but a shooter forced far from the post will have to apply lots more force in the direction of the net as the ball will need greater momentum to travel to the net.

Question 6

define newtons 3rd law on motion

Answer 6

law or action and reaction: for every action there is an equal and opposite reaction

Question 7

give a sporting example of newtons 3rd law

Answer 7

during a bounce pass in netball, the ball travels down towards the floor, on contact, the ball exerts a downward action force on the ground that in turn exerts an upward reaction force on the ball into the hands of the recieving.

Question 8

define a balanced force

Answer 8

2 or more forces acting in opposite direction that are equal in size so there is zero net force

Question 9

define unbalanced force

Answer 9

when the force acting in one direction is larger than the force acting in the opposite direction so a net force is created. `

Question 10

define weight

Answer 10

weight is a gravitational force that exerts on body and vertically pulls it down from the centre of mass

Question 11

hat is the formulae for calculating weight

Answer 11

weight = mass x gravity

Question 12

define rection force

Answer 12

the ground section and opposes the action force.

Question 13

define friction

Answer 13

the anti-flipping force opposes motion when two surfaces pass against one another

Question 14

describe the factors affecting friction

Answer 14

• the roughness of the surfaces in contact
• the roughness of the ground surface
• the greater the down force or mass of an object the greater the friction
• warmth of the surface

Question 15

define air resistance

Answer 15

the force that opposes motion through the air

Question 16

describe the factors that affect air resistance

Answer 16

• the velocity of a moving body
• the frontal cross-sectional area of the moving body
• the shape
• the smoothness of surface characteristics of a moving body

Question 17

formulae for calculating force

Answer 17

force = mass x acceleration

Question 18

formulae for calculating momentum

Answer 18

momentum = mass x velocity

Question 19

formulae for calculating acceleration

Answer 19

acceleration = force x mass

OR \

acceleration = change in velocity / time

Question 20

formulae for calculating weight

Answer 20

weight = mass x acceleration due to gravity (10m/s^2)

Question 21

define centre of mass

Answer 21

the post of balance of a body and how the weight appears to act

Question 22

what factors affect the centre of mass

Answer 22

• distribution of mass
• movement of limbs
• uniformity of the shape

Question 23

describe the factors that affect the relationship between COM and stability

Answer 23

• the height of the COM: lowing COM increases stability
• portion of line of gravity: should be central over base of support to increase stability
• area of the base of support/ more points of contact of base of support: greater the area of the base of support, the greater the stability
• mass of performer: the greater the mass, the more stability due to increased inertia

Question 24

define wind tunnels

Answer 24

a chamber through which air is forced

Question 25

what are advantages of he use of wind tunnels

Answer 25

• equipment and technique can be adapted to increase the aerodynamic properties ( reduce air resistance so increase performance)
• wind speed and direction are controllable to mimic competitive conditions
• individual pieces of equipment can be tested

Question 26

what are disadvantages of the use of wind tunnels

Answer 26

equipment is expensive and usually located in engineering facilities/ research labs
- real life conditions may impact unexpectedly so results are not always realistic