Biomechanical Principles & Linear Motion

Question 1

What is linear motion?

Answer 1

Movement in a straight line

Question 2

How do you calculate speed?

Answer 2

Distance divided by time

Question 3

How do you calculate velocity?

Answer 3

Displacement divided by time

Question 4

How do you work out acceleration?

Answer 4

Change in velocity divided by time

Vf-vi / t

Question 5

What is acceleration measured in?

Answer 5

m/s/s

Question 6

Name Newton’s 3 laws of motion

Answer 6

1st - Inertia
2nd - Acceleration
3rd - Reaction

Question 7

Describe Newton’s 1st Law

Answer 7

Inertia

a body continues in a state of rest or constant motion unless acted upon by an external force

Question 8

Describe Newton’s 2nd Law

Answer 8

Acceleration

the rate pf change of momentum of an object is proportional to the size of the force applied

Question 9

Describe Newton’s 3rd Law

Answer 9

every force exerted by one body onto another has an equal and opposite reaction

Question 10

What is acceleration?

Answer 10

the rate of change of velocity

Question 11

How do you calculate acceleration

Answer 11

change in velocity divided by time

vf-vi / t

Question 12

What is acceleration measure in?

Answer 12

m/s/s

Question 13

How do you measure velocity?

Answer 13

displacement divided by time

Question 14

How do you measure speed?

Answer 14

distance divided by time

Question 15

What is distance?

Answer 15

the path taken from point 1 to point 2

Question 16

What is displacement?

Answer 16

the shortest straight line route from a to b (as the crow flies)

Question 17

What is velocity?

Answer 17

how quickly you can move in a certain direction

Question 18

What is speed?

Answer 18

how quickly you move

Question 19

what are speed and velocity measured in?

Answer 19

m/s

Question 20

If a distance/time graph is a straight horizontal line what does this show?

Answer 20

stationary

Question 21

If a distance/time graph shows a straight diagonal line what does this show?

Answer 21

constant velocity

Question 22

If a distance/time graph curves upwards to the right what does this show?

Answer 22

acceleration

Question 23

If a velocity/time graph shows a straight horizontal line, what does this show?

Answer 23

constant velocity

Question 24

If a velocity/time graph curves upwards to the right what does this show?

Answer 24

acceleration

Question 25

Define the term 'force'

Answer 25

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

Question 26

What is net force?

Answer 26

the overall force acting on a body when all the individual forces have been considered

Question 27

What is a balanced force?

Answer 27

when 2 or more forces acting on the body are equal in size but opposite in direction. The resultant net force is 0

Question 28

What is the resultant net force of a balanced force?

Answer 28

0

Question 29

What is an unbalanced force?

Answer 29

When force acting in one direction is greater in size than a force acting in the opposite direction. The resultant force is either positive or negative

Question 30

Name the 2 vertical forces

Answer 30

weight and reaction

Question 31

Name the 2 horizontal forces

Answer 31

friction and air resistance

Question 32

What is weight force?

Answer 32

the force exerted on a body by the Earth's attraction

Question 33

What is weight measured in?

Answer 33

Newtons

Question 34

What is reaction force?

Answer 34

for every action there is an equal and opposite reaction.

Question 35

Where does the arrow on a free body diagram go for weight?

Answer 35

from the centre of mass (usually around the belly button) down to the floor

Question 36

Where does the arrow on a free body diagram go for reaction?

Answer 36

from the points in contact with the floor upwards. | The bigger the force, the bigger the arrows

Question 37

What is friction?

Answer 37

the force that acts in opposition to the movement of one surface over another

Question 38

What is air resistance?

Answer 38

the force acting in the opposite direction to the motion of a body travelling through air

Question 39

Where does the arrow on a free body diagram go for friction?

Answer 39

from the points in contact with the ground, forwards

Question 40

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

Answer 40

from the centre of mass backwards

Question 41

What factors affect friction?

Answer 41

surface characteristics | temperature of the two surfaces

Question 42

How do surface characteristics affect friction?

Answer 42

``` rough surface (e.g. spikes on an athletics track) increases friction smooth surface (e.g. ski's on ice) reduces friction ```

Question 43

How does temperature of the two surfaces affect friction?

Answer 43

``` an increase in temperature will either increase or decrease friction depending on the surface characteristics skis on snow - an increased temperature reduces friction rubber surfaces (e.g. tyres on a car) - an increase in temperature increases friction ```

Question 44

What is the net force if AR = F?

Answer 44

net force =0 (balanced)

Question 45

What is the net force and direction of motion if AR>F

Answer 45

direction of motion = forwards net force = negative (unbalanced) this means you are decelerating

Question 46

What is the net force if AR

Answer 46

direction of motion = forwards net force = positive (unbalanced) this means you are accelerating

Question 47

What is the net force if W = R?

Answer 47

net force = 0 (balanced)

Question 48

What is the net force and direction of motion if W > R?

Answer 48

Direction of motion = downwards net force = negative (balanced) e.g. you are pushing down into the floor before take off for a jump

Question 49

What is the net force and direction of motion if W < R

Answer 49

Direction of motion = upwards net force = positive (balanced) e.g. you are taking off of the ground in a jump

Question 50

What is Impulse?

Answer 50

Impulse = a product of force x the time it acts for (Ns)

Question 51

What can impulse be increased by?

Answer 51

greater muscular force = greater impulse | greater time a force is applied for = greater impulse

Question 52

What do force/time graphs show?

Answer 52

Impulse

Question 53

What does a negative section on a force/time graph for a high jumper at take off show?

Answer 53

pushing downwards into the ground

Question 54

If the positive section of a force/time graph is greater than the negative section for a sprinter what does this indicate?

Answer 54

that they are accelerating

Question 55

If the negative section of a force/time graph is greater than the positive section for a sprinter what does this indicate?

Answer 55

that they are decelerating

Question 56

If the positive and negative sections of a force time graph are of similar levels for a sprinter what does this show?

Answer 56

they're at a constant / maximum speed