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PE- Mr Mcdarby > 3- Biomechanics > Flashcards

3- Biomechanics Flashcards

1
Q

How topspin in tennis causes the flight path to deviate (use airflow)

A
  • UPPER: airflow is in the opposite direction to the spin of the ball
  • UPPER: low velocity, high pressure
  • LOWER: airflow is in the same direction to the spin of the ball
  • LOWER: high velocity, low pressure
  • gradient going from high pressure to low pressure
  • as a result Magnus force acting downwards
  • Flight path shortens and dips (less time in the air)
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2
Q

One benefit of using topspin in tennis

A
  • hit the ball harder and it will still land in the court
  • can deceive opponents
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3
Q

How does the speed of release and height of release affect the horizontal distance travelled by a projectile

A
  • faster the speed of release the further the projectile travels
  • The higher the release compared to landing the further the projectile travels
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4
Q

two factors affecting the size of the moment of inertia of a rotating body

A
  • mass of the body
  • distribution of mass
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5
Q

using a practical example describe the relationship between moment of inertia and angular velocity

A

Inverse relationship

  • Tucked position in gymnastics somersault : low moment of inertia and high angular velocity
  • Straight position in gymnastic somersault: high moment of inertia and low angular velocity
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6
Q

Define Angular Momentum

A

quantity of angular motion possessed by a rotating body

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7
Q

Define moment of inertia and the measurement used

A

resistance of the body to change its angular motion (kgm^2)

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8
Q

Define Angular velocity

A

rate of change in angular displacement

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9
Q

Four types of force acting on a cyclist while they pedal forwards

A
  • Weight (Down from COM)
  • Reaction (up from both wheels)
  • Air resistance (backwards from COM)
  • Friction (forwards from ground on both wheels)
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10
Q

Use angular analogue of Newtons 1st law of motion to explain how the skater can increase rate of spin

A
  • skater brings arms or legs in (closer to longitudinal axis)
  • reducing moment of inertia
  • increasing angular velocity
  • principle of conservation of angular momentum
  • AM= MI x AV
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11
Q

How a ski jumper can apply Bernoullis principle to maximise the distance travelled

A
  • adopts an aerofoil shape
  • create an angle of attack (17 degrees)
  • UPPER: air travels further
  • UPPER: higher velocity and lower pressure
  • LOWER: lower velocity and a higher pressure
  • air travels from high to low
  • Lift force created
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12
Q

What is the equation and the units for angular velocity

A

angular displacement / time

rads -1

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13
Q

Explain how a golfer creates a hook shot and the effect on the flight path

A
  • Eccentric force
  • causes side spin
  • LEFT SIDE: higher velocity and lower pressure
  • RIGHT SIDE: lower velocity and higher pressure
  • air travels from high to low pressure
  • Magnus force
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14
Q

factors other than mass that impact on the air resistance of a ball in flight

A
  • velocity
  • shape (more aerodynamic)
  • greater frontal cross sectional area
  • the smoother the surface
  • spin
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15
Q

metric units of measurement for displacement and acceleration

A

Displacement: metres
Acceleration: m/s squared

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16
Q

Describe linear motion and angular motion

A
  • linear motion : movement of a body in a straight or curved line
  • Angular motion : movement of a body in a circular path
17
Q

factors that affect the size of moment of inertia of the trampolinist during a somersault

A
  • mass
  • Distance/distribution of mass
18
Q

Three factors that affect the horizontal distance travelled by a shot in flight

A
  • Speed of release: greater speed
  • Angle of release: just under 45 degrees
  • Height of release: greater the release height
19
Q

Explain the shape of the flight path of the shot putt

A
  • parabolic flightpath
  • weight is the dominant force (mass is high)
  • Air resistance will be low
20
Q

identify vertical forces acting on the gymnast and explain their relationship during the handstand

A
  • weight and reaction
  • W=R
  • Forces are equal and opposite (net force = 0)
21
Q

Define angular motion and how it is generated to produce a somersault

A
  • movement of a body about an axis of rotation
  • Force applied outside the COM (eccentric force)
22
Q

Use the angular analogue of newtons first law of motion to explain the concept of conservation of angular momentum

A
  • body will continue to rotate about it’s axis of rotation with constant angular motion
  • unless an eccentric force is applied
  • Angular momentum= moment of inertia x AV
  • once in flight any change to the moment of inertia will cause change in the AV in order to conserve angular momentum
  • the performer can change the moment of inertia by manipulating body shape.
23
Q

Identify two types of spin and the effect of each on a table tennis ball in flight

A
  • Top spin (ball to dip, comes down more quickly)
  • Back spin (longer flight path, travel further)
23
Q

Identify ways that a swimmer can minimise drag

A
  • reduce frontal cross-sectional area
  • streamline
  • reduce surface affects (smooth surface)
  • reduce speed
24
Q

State Bernoulli’s principle and apply it to an F1 racing car

A

The higher the velocity of air flow the lower the pressure, all gases move from an area of high to low pressure (down a pressure gradient)

  • Spoiler is used
  • angle of attack 17 degrees
  • low pressure high velocity under spoiler
  • high pressure low velocity above spoiler
  • therefore pressure goes from high to low
  • enabling the car to hold the road and go round bends at higher speeds
25
Q

A 4 × 400 metre relay race takes place on a standard 400 metre track and the baton is correctly passed between the four runners.

Calculate the distance covered and displacement of the baton during the race.

A

Displacement = 0
Distance = 1600 metres

26
Q

Describe a first class lever with a sporting example

A
  • the neck when heading a football
  • the fulcrum is located in between the effort and the load
  • effort: Muscles at the back of the neck
  • load: The head
  • fulcrum: the neck
27
Q

Describe a second class lever with a sporting example

A
  • a calf raise
  • load is located between the fulcrum and the effort
  • Load: body weight
  • Effort: calf muscles
  • Fulcrum: balls of the foot
28
Q

Describe a third class lever with a sporting example

A
  • elbow during a bicep curl
  • effort is located between the load and the fulcrum
  • Fulcrum: elbow
  • Effort: bicep brachii
  • Load: dumbell in hand
29
Q

What is mechanical advantage

A
  • ratio of effort arm to the load arm defines the mechanical advantage
  • less effort is needed to move the load
30
Q

what two lever systems provide mechanical advantages and are used for strength related movements

A
  • first class and second class movements
31
Q

What lever system provides a mechanical disadvantage and is used for movements that require speed and range of motion

A

third class levers

32
Q

Define Newtons first law

A
33
Q

Define Newtons second law

A
34
Q

Define Newtons third law

A

PE- Mr Mcdarby (14 decks)

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