biomechanical principles + fluid mechanics

Question 1

what is Newton’s first law?

Answer 1

law of inertia
A body will remain at rest or constant velocity until an external force is exerted on it

Question 2

what is Newton’s second law?

Answer 2

law of acceleration
the acceleration of a body is proportional to the force causing it and the acceleration takes place in the direction which the force acts
F=ma

Question 3

what is Newton’s third law?

Answer 3

law of reaction
for every action, there’s an equal and opposite reaction

Question 4

what are the 5 ways a force can change state of motion?

Answer 4

stationary body to move
moving body to slow down
moving body to speed up
moving body to change direction
body to change shape

Question 5

what are the four factors effecting friction?

Answer 5

roughness of ground surface
roughness of contact surface
temperature
size of normal reaction

Question 6

how does roughness of ground surface effect friction? and example

Answer 6

a rougher surface=more friction
eg. athletics tracks are rough
ice rinks are smooth

Question 7

how does roughness of contact surface effect friction? and example

Answer 7

a rougher contact surface=more friction
eg. cross country spikes, smooth wheels on road bikes, smooth ski surface

Question 8

how does temperature effect friction? and example

Answer 8

higher temperatures of certain materials will create more friction
eg. F1 cars warm up lap/tire blankets
ice is cooler so less friction curling/ speed skating

Question 9

how does the size of the normal reaction effect friction? and example

Answer 9

an athlete having higher mass, creates larger reaction force which increases friction
eg. shot putters high mass stops slipping

Question 10

what are the four factors effecting air resistance?

Answer 10

velocity
frontal cross-sectional area
streamlining and shape
smoothness of surface

Question 11

how does velocity effect air resistance in cycling and swimming?

Answer 11

cycling: the greater the velocity, the greater the air resistance

swimming: the greater the velocity, the greater the drag

Question 12

how does frontal cross-sectional area effect air resistance in cycling and swimming?

Answer 12

cycling: time trial position/ peloton making themselves small decreases air resistance

swimming: during diving they have a flat body position, turn their head to breath

Question 13

how does streamline and shape in cycling and swimming help reduce air resistance?

Answer 13

cycling: curved helmets, time trial position to create aerofoil shapes creating smooth airflow which reduces air resistance

swimming: diving with arms above head, swimsuits, swim hats decrease AR

Question 14

how does smoothness of surface help reduce air resistance in cycling and swimming?

Answer 14

cycling: lycra clothing, smooth helmets, type of tires

swimming: shave their hair, tight swimsuits and swim hats to reduce AR

Question 15

what is centre of mass?

Answer 15

the point where the mass of a body tends to be concentrated and is balanced in all directions

Question 16

what are the 4 factors effecting stability?

Answer 16

mass of the body
height of the CoM
base of support
line of gravity

Question 17

what is stability?

Answer 17

the ability of the body to resist motion and remain at rest in a balanced position

Question 18

how does mass of the body effect stability? and example

Answer 18

the greater the mass, the more stable the body is
eg. sumo wrestler will have a high mass to increase stability

Question 19

how does height of CoM effect stability? and example

Answer 19

the lower the centre of mass, the more stable a body is
eg. in a rugby scrum, players crouch down to lower CoM and increase stability

Question 20

how does base of support effect stability? and example

Answer 20

the larger the base of support, the more stability a body has
eg. a gymnast doing a wide grip handstand will be more stable

Question 21

how does line of gravity effect base of support? and example

Answer 21

the closer the line of gravity to the base of support, the more stable a body is
eg. a diver leaning over about to dive wants to be less stable so move their line of gravity outside base of support