biomechanical principles

Question 1

what is force

Answer 1

a push or pull that alters the state of motion of a body

Question 2

what is the equation and units for force

Answer 2

mass x acceleration → N

Question 3

what is inertia

Answer 3

the resistance of a body to change its state of motion whether at rest or while moving

Question 4

what is velocity

Answer 4

the rate of change in displacement

Question 5

what is the equation and units for velocity

Answer 5

displacement/time → m/s

Question 6

what is momentum

Answer 6

the quantity of motion possessed by moving a body

Question 7

what is the equation and units for momentum

Answer 7

mass x velocity → kg/m/s

Question 8

what is acceleration

Answer 8

the rate of change of velocity

Question 9

what is the equation and units for acceleration

Answer 9

(final velocity - initial velocity)/time → m/s^

Question 10

what is newton’s first law

Answer 10

“a body continues in a state of rest or uniform velocity unless acted upon be an external or unbalanced forces”

Question 11

what is newton’s second law

Answer 11

“a body’s rate of change in momentum is proportional to the size of the force applied and acts in the same direction as the force applied”

Question 12

what is newton’s 3rd law

Answer 12

“For every action force applied to a body there is an equal and opposite reaction force”

Question 13

what is internal force

Answer 13

generated by the contraction of skeletal muscle

Question 14

what is external force

Answer 14

generated from outside the body and acts upon it

Question 15

what is a balanced net force

Answer 15

net force = 0, no change in motion

Question 16

what is an unbalanced net force

Answer 16

net force ≠ 0, change in motion

Question 17

what are the vertical forces

Answer 17

• weight
• reaction forces

Question 18

what is weight

Answer 18

the gravitational pull that the earth exerts on a body

Question 19

what is the equation and units for weight

Answer 19

mass x acceleration due gravity (10) –> N

Question 20

what is reaction/reaction forces

Answer 20

• equal and opposite force exerted by a body in response to the action force placed upon it and is measured in newtons
• Ground reaction forces (GRF) → has an impact on performer + body

Question 21

what are the horizontal forces

Answer 21

• friction
• air resistance

Question 22

what is friction and what are the units

Answer 22

• the force opposing motion of two surfaces in contact
• contact between two opposing surfaces
• N

Question 23

what is air resistance and what are the units

Answer 23

• the force opposing motion travelling through air.
• It is a form of fluid friction
• N

Question 24

what is center of mass (CoM)

Answer 24

the point at which a body is balanced in all directions; the point from which weight appears to act.

Question 25

what is stability

Answer 25

- the ability of a body to resist motion and remain at rest - or for a body to withstand a force applied and return to its original position without damage.

Question 26

what are the factors that affect stability

Answer 26

- Mass of body - Height of CoM - Base of support - Line of gravity

Question 27

how does mass of body affect stability

Answer 27

greater mass, greater stability

Question 28

how does height of CoM affect stability

Answer 28

lower CoM, greater stability

Question 29

how does base of support affect stability

Answer 29

Greater size of BoS, greater stability

Question 30

how does line of gravity affect stability

Answer 30

more central LoG, greater stability

Question 31

on a free body diagram where does the arrow for weight go

Answer 31

From the CoM extending vertically downwards

Question 32

on a free body diagram where does the arrow for reaction forces (GRF) go

Answer 32

From the point of contact extending vertically upwards - if 2 wheels there will be 2 arrows bt half the length as they both add up to make a full one

Question 33

on a free body diagram where does the arrow for friction go

Answer 33

From the point of contact usually extending horizontally in the same direction as motion

Question 34

on a free body diagram where does the arrow for air resistance go

Answer 34

From the CoM and extending horizontally against the direction of motion

Question 35

what happens if the air resistance (arrow) is larger than the friction (arrow)

Answer 35

net force is negative - slowing down/decellerating