Chapter 4

Question 1

Projectile

Answer 1

Is a body or an object that is launched into the air but is only affected by forces of gravity or air resistance

Question 2

Projectile Motion

Answer 2

Refers to the flight path and the factors that affect a projectile

Question 3

Give an example of a vertical component

Answer 3

High Jump

Question 4

Explain Vertical Component

Answer 4

• The height in which a projectile reaches
• It is influenced by gravity and the initial projection velocity
• A projectile motion will slow as it goes up but speeds up as it comes down, this gives it a parabolic flight path
• Acceleration due to gravity (9.8m/s) is the same regardless of size, height and shape.

Question 5

How is the final speed impacted if an object is thrown and caught at the same height?

Answer 5

The speed stays the same as the initial speed

Question 6

Give an example of a horizontal component

Answer 6

Long jump

Question 7

Horizontal Component

Answer 7

• The distance in which a projectile covers
• Affected by air resistance
• If no air resistance took place, the horizontal velocity of an object would stay the same

Question 8

Factors affecting the path of a projectile:

Answer 8

Coaches will often manipulate these factors so that the athletes can achieve the best results

Question 9

Angle of Release

Answer 9

• The angle in which an object is projected into the air

- It influences flight path and horizontal distance

Question 10

Three Shapes that a Flight Path can Form

Answer 10

1. Vertical, straight up and back down
   - 90 degrees
   - eg a vertical jump
2. Parabolic, a semi-circle like shape
   - between 0-90 degrees
   - eg golf swing
3. Horizontal, an object projected that is perfectly horizontal
   - 0 degrees
   - eg bowling a cricket ball

Question 11

What does the angle have to be if an object is to travel over something higher than ground level?

Answer 11

45 degrees

-eg high jump

Question 12

Speed of Release

Answer 12

• The speed in which an object is thrown, kicked or propelled into the air
• Release speed has both a horizontal and vertical component

Question 13

Speed of Release- Vertical Component

Answer 13

Determines the height reached and flight time

Question 14

Speed of Release- Horizontal Component

Answer 14

Determines the horizontal distance covered by the projectile

Question 15

What is the affect on the projectile if the speed of release increases?

Answer 15

Horizontal range also increases

Question 16

Height of Release

Answer 16

Refers to the difference between the height in which a projectile is released and the height where the projectile stops or land
Optimal angle of release depends on the height of release
Determines the distance an object will travel
-if the angle and speed of release are constant then the larger the height of release, the further a projectile will travel
-generally the higher the height of release the lower the angle of release

Question 17

Height of Release examples

Answer 17

a volleyball player who performs a jumping spike is up very high yet, the angle in which the ball is sent is downwards meaning the angle of release is quite small

Question 18

Flight path of a long jump

Answer 18

Study of long jump has shown that the optimal angle of release (45 degrees) for maximal distance does not apply

Question 19

How do athletes achieve the optimal angle of 45 degrees?

Answer 19

Athletes would have to decrease their velocity by half which in turn decreases the horizontal distance achieved (principle of speed of release)

Question 20

Why do athletes need to lower their angle of release to achieve optimum 45 degrees?

Answer 20

The reason for the lower angle of release is due to the height of the centre of gravity. It starts off higher than the end. Therefore, athletes have adapted to this by optimising their height, leg length and strength/power.

Question 21

General Motion

Answer 21

A combination of both linear and angular motion

It is easier to analyse movements that have been broken into separate linear and angular segments

Question 22

Linear Motion

Answer 22

Refers to the movement of all body parts at the same speed along a rectilinear or curvilinear line
Most aspects of linear motion are quantitative

Question 23

Rectilinear Line

Answer 23

Straight line

Question 24

Curvilinear Line

Answer 24

Curved Line

Question 25

Linear Distance

Answer 25

The measurement of the path from start to finish. Measured in metres

Question 26

Linear Displacement

Answer 26

Measurement of the change of a bodies or objects initial position to its final position. Measured in metres in a particular direction

Question 27

Is distance or displacement more valuable data?

Answer 27

Distance

Question 28

Linear Speed

Answer 28

The ratio of distance to time taken | Measured in metres /second

Question 29

Linear Speed=

Answer 29

distance/ time

Question 30

Velocity

Answer 30

The ratio of change in position (displacement) to time taken. Measured in metres / second with a direction

Question 31

Velocity=

Answer 31

displacement/time

Question 32

A change in speed is due to...

Answer 32

speed

Question 33

A change in velocity is due to...

Answer 33

changes in speed, direction or both

Question 34

Linear Acceleration

Answer 34

A change in velocity over a given period of time Measured in metres/second^2 Can be pos/neg (deceleration)

Question 35

Acceleration=

Answer 35

change in velocity/ change in time

Question 36

Give an example of acceleration in sport

Answer 36

Sprinter will accelerate to reach their top speed quickly

Question 37

Give an example of deceleration in sport

Answer 37

a mountain bike rider will decelerate into turns to stay balanced

Question 38

Explain when acceleration=0

Answer 38

When acceleration=0 it doesn't necessarily mean that the body or object isn't moving. The object or body just isn't slowing down or speeding up. 0 acceleration results in a constant velocity

Question 39

In velocity/ time graphs, what happens when the line goes below the x axis?

Answer 39

The body or object has changed direction

Question 40

Angular Motion

Answer 40

Refers to movement around a central axis or fixed point | Eg walking-leg rotates around hip joint

Question 41

How do linear and angular movements interrelate?

Answer 41

Lots of linear movements are the result of angular movements of body parts

Question 42

Axis of Rotation cam be:

Answer 42

- Real: a gym bar - Imaginary: Centre of gravity - Internal: joints of the body - External: Centre of gravity

Question 43

Angular Motion is caused by...

Answer 43

Angular motion is caused by an eccentric force, a force applied outside of the centre of mass causing an object to rotate and move forwards

Question 44

Torque

Answer 44

The tendency of an object to rotate AKA moments of force

Question 45

Torque=

Answer 45

Force x lever arm (perpendicular distance from axis of rotation to force)

Question 46

Torque size is influenced by...

Answer 46

lever arm and the size of the applied force

Question 47

Torque's cause a greater...

Answer 47

angular acceleration and rotation around an axis | increasing rotation is beneficial

Question 48

What happens when eccentric forces are applied?

Answer 48

Objects spin | These forces cause objects to deviate from their original path

Question 49

Three types of axis

Answer 49

1. Longitudinal, runs from top to bottom 2. Frontal, runs from front to back 3. Transverse, runs from side to side across the body

Question 50

Eccentric Force

Answer 50

A force that does not act through an object's centre of gravity Cause objects to rotate and move forward

Question 51

Angular Distance

Answer 51

The sum of all angular changes a body or object undergoes. | Measured in degrees

Question 52

Example of angular distance

Answer 52

a 1 and a half somersault is a total angular distance of 540 degrees

Question 53

Angular Displacement

Answer 53

The difference between the initial position and final position of a body or object. Measured in degrees with a direction

Question 54

Example of angular displacement

Answer 54

a 1 and a half somersault has a total angular displacement of 180 degrees

Question 55

Angular Speed

Answer 55

The ratio of angular distance covered to the time taken to complete the motion measured in degrees/second.

Question 56

Example of angular speed

Answer 56

It takes three seconds for one and a half circles to be completed, the angular speed would be 180d/s

Question 57

Angular Velocity

Answer 57

The ratio of the rate of change in the angular displacement to time. Measured in degrees per second in a direction

Question 58

Example of angular velocity

Answer 58

It takes 3 seconds for one and a half circles to be completed the angular velocity is 60d/s

Question 59

Give an example of how angular velocity increases as the skill gets more difficult

Answer 59

A single rotation has lesser velocity than a triple rotation

Question 60

What is the relationship between linear and angular velocity?

Answer 60

To increase an objects linear velocity, it is critical to increase the angular velocity of each body part used in the motion as it will increase the final velocity at point of release

Question 61

Linear Velocity=

Answer 61

Radius of rotation x angular velocity

Question 62

How does increasing the radius of rotation affect linear velocity?

Answer 62

Increases

Question 63

How can the radius of rotation be increased?

Answer 63

By increasing the length of the radius, yet if the equipment used to elongate the radius is too heavy, then the angular velocity is compromised as the equipment cannot be swung as quickly

Question 64

Angular Acceleration

Answer 64

Refers to the rate of change of angular velocity or how quickly a body or object changes its angular position Measured in degrees per second

Question 65

How can angular acceleration be changed?

Answer 65

Via the changing of the size or the direction of the acceleration