Biomechanics

Question 1

how is force calculated?

Answer 1

F=ma
N = Kg x m/s

Question 2

What is Newton’s first law and give sporting examples? (3)

Answer 2

Law of inertia
‘ an object stays in motion at the SAME speed/direction and an object at rests stays at rest, unless ACTED UPON BY AN EXTERNAL FORCE’

EG:
an object/body at REST TO MOVE : serving in TENNIS ( first you’re still, then lift arm to serve)
RUNNING (on blocks, then start running)

a moving object CHANGING DIRECTION, accelerate or decelerate : TENNIS - hit ball to change direction/ run towards net and decelerate

an object to CHANGING SHAPE : SQUASH - ball changes shape when hit

Question 3

What is Newton’s 2nd law and give sporting examples? (2)

Answer 3

Law of acceleration
‘An object will accelerate when acted on by an external force. The acceleration of an object is proportional to the force and is in the direction by which the force acts.’

EG:
CURLING ; stone pusher pushes the stone (the external force)
the sweepers sweep the floor to accelerate (external force)

Question 4

What is Newton’s 3rd law and give sporting examples? (2)

Answer 4

Law of motion
‘for every action, there exists an equal and opposite reaction’

EG:
HOCKEY
- a hockey player collides with an opponent
- the hockey player experts a force on the opponent and the opponent will exert an equal force back.
- this will decelerate the opponent / accelerate the player in the opponent’s direction

Question 5

What is gravity?

Answer 5

force that attracts the body toward the centre of the earth

Question 6

Muscular force?

Answer 6

a push/pull applied on the object provided by muscular contraction

Question 7

air resistance?

Answer 7

the frictional force that air applies against a moving object

Question 8

ground reaction force?

Answer 8

the reaction to the force that the body exerts on the ground

Question 9

WHta happens when the forces are unbalanced?

Answer 9

the object will start to accelerate or move in the direction which the larger force is pushing/pulling it

Question 10

What causes the acceleration phases for a runner ?

Answer 10

When forces go from BALANCED -> UNBALANCED
e.g. in running, pushing against blocks creates ground reaction force, which creates an explosive start
muscular force is much greater than air resistance

Question 11

What causes the MAX SPEED for an athlete?

Answer 11

As speed increases/muscular force reaches its OPTIMUM balance against air resistance, acceleration stops/ max speed is reached.

Question 12

what is a lever?

Answer 12

a solid bar that turns around on an axis to create movement and contains 3 main components : fulcrum, resistance and effort

Question 13

what is a fulcrum?

Answer 13

a fixed point about which a lever can turn

Question 14

what is resistance?

Answer 14

the load or weight that the lever must move

Question 15

what is effort ?

Answer 15

the amount of force required to move the load

Question 16

how does a 1st class lever work and give sport example? (2)

1 2 3
F R E

Answer 16

• fulcrum in the middle and resistance and effort on either side of the fulcrum

E.G: ROWING
effort : man applies force to pull ores
fulcrum: sides of rowing boat where ores sit
resistance: water resistance

Question 17

how does a 2nd class lever work/ ADVANATGE and give sport example? (3)

1 2 3
F R E

Answer 17

Resistance is in-between effort and fulcrum

AD: effort to move the load can be much less than the moving load itself.

E.G: CALF RAISES
effort : force supplied by gastrocnemius contraction
fulcrum : ball of foot/joints in toes
resistance: weight of body going through foot

Question 18

how does a 3rd class lever work/ DISADVANTAGE and give sport example? (3)

1 2 3
F R E

Answer 18

Effort is in-between resistance and fulcrum

DIS: require more effort, greater range of motion, increased speed to perform a task

E.G: bicep curl
effort : bicep contraction
resistance : the weight lifted
fulcrum: elbow joint