Deck 3: Kinematics and Kinetics of Angular Motion

Question 1

Angular motion is defined as:

A) the rotation and translation of an object
B) an axis of rotation
C) the translatory movement of an object
D) the movement along a straight line
E) the rotatory movement of a body about an axis of rotation

Answer 1

E
Explanation: Angular motion is the rotatory movement of an object or body about a real or imaginary axis of rotation

Question 2

One radian is approximately:

A) 100 degrees
B) 57.3 degrees
C) 35.4 degrees
D) 3.14 degrees
E) 0 degrees

Answer 2

B
Explanation: one radian is derived from 2π radians = 360 degrees. Hence 360/2π = 57.3

Question 3

How many radians are there in one circle?

A) 2π
B) 3.14π
C) 57.3π
D) 360π
E) π

Answer 3

A
Explanation: one radian is derived from 2π radians = 360 degrees

Question 4

Angular velocity is measured in:

A) degrees/s
B) degrees x seconds
C) degrees squared
D) degrees
E) radians

Question 5

Angular acceleration is:

A) angular velocity/time
B) angular displacement/time
C) time/angular velocity
D) angular velocity/radians
E) displacement/time

Question 6

Clockwise rotation is usually given a positive sign

Question 7

Anticlockwise rotation is the same direction as the movements of the hands of a clock

Question 8

Angular displacement has magnitude and direction

Question 9

36 degrees is 0.63 radians

Question 10

There are 67.3 degrees in one radian

Question 11

Most sporting movements only have translatory motion

Question 12

The upper leg of a soccer player moves through 115 degrees in 0.46 seconds during the kicking of a soccer ball. What is the average angular velocity of the upper leg in this example?

Question 13

Explain how sporting movements involve both rotational and linear motion.

Question 14

If the angular velocity of a limb at point 1 (time = 0.30 seconds) is 113 deg/s and then it increases to 156 deg/s at point 2 (0.76 seconds) what is the average angular acceleration between the two points?

Question 15

Explain what is meant by the terms clockwise and anti-clockwise motion.

Question 16

Explain how it is possible to have a vector quantity in angular motion.

Question 17

The relationship between linear and angular distance is given by:

A) s=rθ
B) v=rt
C) a=θr
D) s=v/t
E) s=vr

Question 18

The reltaionship between linear velocity and angular velocity is given by:

A) v=sr
B) ω=ɑr
C) v=ωr
D) v=d/t
E) v=sω

Question 19

The relationship between linear acceleration and angular acceleration is given by:

A) a=rω
B) a=v/t
C) a=ɑr
D) a=sr
E) ɑ=ω/t

Question 20

An arm moves clockwise through 48° in 1.79s - what is the average angular velocity?

A) 34°/s
B) 100°/s
C) 0.77 rads/s
D) 0.47 rads/s
E) 1.90 rads/s

Question 21

Two points are located on a rigid body that rotates through 56°. Point A is 0.67 m from the axis of rotation and point B is 0.65m from the axis of rotation - which point moves the furthest linear distance?

A) both move the same linear distance
B) none of the points
C) point B
D) point C
E) point A

Question 22

There is no relationship between linear and angular motion and they work independently of each other

Question 23

Angular Velocity is defined as Angular Acceleration divided by Time

Question 24

Angular distance is the arc length of the curve created by angular motion of a rigid body

Question 25

A point that is closer to the axis of rotation of a rigid body will move a shorter linear distance than a point that is further away from the axis of rotation

Question 26

It is possible to have an angular orientation of a point

Question 27

A tangent is defined as a line that touches a curve at a point and the line will have the same gradient (slope of a line measured as its ratio of vertical to horizontal change) as that of the curve at that point.

Question 28

Three points are located on a rigid body that moves through 87° in 2.45s. Point A is 0.76m; point B is 0.86m and point C is 0.96m from the axis of rotation respectively. Determine the linear distance moved by each point?

Question 29

Determine the linear velocity of the three points from question 1.

Question 30

Determine the angular velocity of points A, B and C.

Question 31

Explain what is meant by the term Tangential linear velocity.

Question 32

Explain what is meant by the term at a Tangent in this context of rotating bodies and linear velocity.

Question 33

Torque is defined as:

A) a force
B) a distance
C) a turning moment
D) a velocity
E) an acceleration

Question 34

A moment is defined as:

A) force x velocity
B) force x acceleration
C) force x torque
D) force x perpendicular distance
E) torque x distance

Question 35

Clockwise rotation is:

A) movement in a straight line
B) movement in the vertical direction
C) movement opposite to the hands of a clock
D) movement in the horizontal direction
E) movement in the same direction as the hands of a clock

Question 36

A couple is:

A) a single force
B) three different forces
C) two equal and opposite forces
D) four opposing forces
E) no forces

Question 37

Force is measured in:

A) m/s
B) Nm
C) deg/s
D) s
E) N

Question 38

Clockwise rotation is given the following sign:

A) negative
B) positive
C) negative and positive
D) neither positive nor negative
E) no sign

Question 39

Torque is a vector quantity

Question 40

Moments are measured in Newtons

Question 41

Torques are necessary to cause rotational movement

Question 42

Anti-clockwise rotation is the same direction as the hands of a clock

Question 43

The see-saw is a good example of moments

Question 44

A force of 25N acting at a perpendicular distance of 0.6m produces a moment of 41.6N/m

Question 45

Determine the torque acting on the elbow joint from a muscle force of 345N applied at a perpendicular distance of 0.05m from the elbow joint axis of rotation

Question 46

if person A, who was 55kg, was sitting 1.7m from the fulcrum of a see-saw, try and balance the see-saw for a 75kg person sitting at the opposite side of the fulcrum from person A

Question 47

Explain the first condition of equilibrium in linear motion

Question 48

Explain the first and second conditions of equilibrium in angular motion

Question 49

Provide some examples of the application of torque and moments in sport and exercise

Question 50

A first class lever is when the force and resistance are:

A) Located at separate sides of the fulcrum.
B) Located on the same side to the right of the fulcrum.
C) Located on the same side to the left of the fulcrum.
D) Not related to the fulcrum at all.
E) On the same side, be it at the right or left of the fulcrum.

Question 51

A third class lever is:

A) Similar to a first class lever.
B) Different to both a first and a second class lever.
C) Similar to a second class lever with both the force and resistance on the same side of the fulcrum.
D) Similar to a first class lever but with the force and resistance at equal distances from the fulcrum.
E) Where the force is not on the lever arm at all.

Question 52

In a second class lever system there is a mechanical advantage in favour of:

A) The resistance.
B) The force.
C) Both force and resistance.
D) The fulcrum.
E) Neither force or resistance.

Question 53

Flexion of the elbow joint is a good example of:

A) A third class lever.
B) All three levers.
C) A first class lever.
D) No levers.
E) A first and second class lever.

Question 54

A see-saw is a good example of a first class lever.

Question 55

An oar for rowing (fulcrum fixed on the side of the boat) is a good example of a first class lever.

Question 56

A shovel used to dig the garden is a good example of a third class lever.

Question 57

A pair of scissors is a good example of a second class lever.

Question 58

Explain mechanical advantage

Question 59

Explain mechanical advantage in terms of force

Question 60

Give four examples of the use of levers in sport and exercise

Question 61

When a discus thrower begins his throwing motion, he spins with an angular velocity of 7 rad/s. Just before he releases the discus this increases to 21 rad/s. If the time from the beginning of the throw to just before release is 0.75 s, what was the thrower's average angular acceleration?

A) 10.5 rad/s²
B) 28 rad/s²
C) 14 rad/s²
D) 18.7 rad/s²
E) 37.3 rad/s²

Question 62

A hammer thrower spins with an angular velocity of 1800°/s. The distance from his axis of rotation to the hammer head is 1.5 m. What was the centripetal acceleration of the hammer head?

A) 47.1 m/s²
B) 31.4 m/s²
C) 1080 m/s²
D) 1480 m/s²
E) 2700 m/s²

Question 63

The lower leg rotates with a constant angular velocity about the knee. Which of the following statements is true in this situation?

A) The limb's angular acceleration is zero, but its centripetal acceleration and tangential acceleration are not zero
B) The limb's angular acceleration and centripetal acceleration are zero, but its tangential acceleration is not zero
C) The limb's angular acceleration is zero, its centripetal acceleration is not zero, and it's tangential acceleration is zero
D) The limb's angular acceleration, centripetal acceleration, and tangential acceleration are all zero
E) The limb's angular acceleration, centripetal acceleration, and tangential acceleration are all not zero

Question 64

When rotating about a high bar a gymnast's centre of mass is 0.724 m away from the bar, and their body angle changes from 48° to 56.7° in 0.04 s. Calculate: i) the angular velocity in both deg/s and rad/s; and ii) the centripetal acceleration.

A) 218 deg/s, 3.80 rad/s & 10.43 m/s²
B) -218 deg/s, -3.80 rad/s & 10.43 m/s²
C) 218 deg/s, -3.80 rad/s & 10.43 m/s²
D) 218 deg/s, 3.80 rad/s & -10.43 m/s²
E) -218 deg/s, -3.80 rad/s & -10.43 m/s²

Question 65

Linear momentum is defined as:

A) mass x linear velocity
B) angular velocity x weight
C) mass/weight
D) weight x linear velocity
E) angular acceleration x mass

Question 66

Angular momentum is defined as:

A) weight x moment of inertia
B) moment of inertia x angular velocity
C) angular velocity x linear velocity
D) mass x linear velocity
E) weight x angular velocity

Question 67

Moment of inertia is related to:

A) the distribution of mass about the axis of rotation
B) the angular velocity of the limb
C) the resistance offered by an object to rotate
D) mass and radius of gyration
E) All of these

Question 68

The moment of inertia of a 25kg mass rotating about a point 3.6m from the axis of rotation is:

A) 25×3.6
B) 25²×3.6
C) 25×25
D) 25²×3.6²
E) 25×3.6²

Question 69

The parallel axis theorem used to calculate the moment of inertia about axis A is derived by:

A) IA = m² + md²
B) IA = IC of G
C) IA = IC of G + md²
D) IA = md²
E) None of these

Question 70

If the moment of inertia of the upper leg, lower leg and foot are respectively 1.20 kg.m², 0.98 kg.m² and 0.54 kg.m², the moment of inertia of the whole leg is:

A) 27.2 kg.m²
B) 2.72 kg.m²
C) 272.0 kg.m²
D) 0.272 kg.m²
E) none of these values

Question 71

Angular momentum is moment of inertia × angular velocity

Question 72

Angular momentum is represented by the letter A

Question 73

Angular momentum is measured in the units of kg.m²/s

Question 74

If there is zero angular velocity then there is zero angular momentum

Question 75

During movement of the body, the total angular momentum possessed by the body (in the absence of any external force) remains constant

Question 76

If an athlete is rotating in a tucked position during a dive and they then extend their body, their moment of inertia about the axis of rotation will?

Question 77

If an athlete is rotating in a tucked position during a dive (in the air) and they extend their arms, their angular velocity (rotation) about the axis of rotation will?

Question 78

If an athlete has a total moment of inertia of 22.4 kg.m² and they are rotating in the air about an axis with an angular velocity of 4.7 rads/s, what will be their angular momentum?

Question 79

Give three examples of changing moment of inertia within sporting performance

Question 80

Which would have a higher moment of inertia value about the longitudinal (head to toe) axis of rotation: Arms out fully extended to the sides or one arm out to the side and one arm down by the side of the athlete?