Your SlideShare is downloading. × Shared Resource
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.

Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply Shared Resource


Published on

1 Like
  • Be the first to comment

No Downloads
Total Views
On Slideshare
From Embeds
Number of Embeds
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

No notes for slide


  • 1. Mechanics of movement A2 Sports Studies Mr Jennings
  • 2. What you need to know…..
    • Mechanics of movement
    • Vectors and scalars; velocity, acceleration
    • Momentum/impulse in sprinting
    • Newton’s Laws applied to movements
    • Application of forces in sporting activities
  • 3.
    • This is a daunting topic
    • However, the questions always focus on very similar scenarios
    • Very quickly you will become familiar with the key terms and concepts
  • 4. Forces
    • A force is:
    • “ A force is that which alters or tends to alter a body’s state of rest or of uniform motion in a straight line.”
    • If a body changes direction or velocity, a force has been applied to it
  • 5.
    • All performance are affected by forces
    • How is this athlete affected by forces?
    • Forces cause us to move, change direction and to stop. Gravity keeps her on the floor
  • 6. Key Terms
    • Displacement
    • Velocity
    • Acceleration
  • 7. Displacement or Distance A B Length of journey in meters = Straight line from start to finish in meters = distance displacement
  • 8. Displacement and distance
    • In a 400m race?
    • In a 400m race on a track the length of the path the athlete follows (distance) is 400m but their displacement will be zero metres (they finish where they start)
  • 9. Speed or velocity
    • Speed is distance / time
    • Velocity is displacement divided by time
    • Displacement has direction
    • Most biomechanics refers to displacement and velocity
  • 10. Speed and velocity
    • Consider a swimmer in a 50m race in a 25m length pool who completes the race in 60 seconds
    • Work out her speed and her velocity
    • Distance is 50m and displacement is 0m (swimmer is back where they started) so speed is 50/60= 0.83m/s and velocity is 0/60=0 m/s
  • 11. Physics of sprinting
    • An athlete runs 100m in 15 seconds
    • We know their speed is 100/15 = 6.67(ms-1)
    • Velocity is a similar concept to speed but includes the idea of ‘direction’
    • All velocities take place in a certain direction
    • Velocity = displacement/time
    • An athlete running 100m in 12s: Velocity = 100/12 = 8.33(ms-1)
  • 12. Calculating velocity
    • Use 100-metre sprinting to calculate athlete’s velocity
    • Plot the velocity curve
    • What do you notice?
  • 13. 12.6 10 100 11.0 10 90 9.6 10 80 8.3 10 70 7.1 10 60 6.0 10 50 5.0 10 40 4.0 10 30 2.9 10 20 1.7 10 10 0 0 Start Time to reach this point (seconds) Distance covered (Metres) Timing point (displacement in metres)
  • 14. What happened?
    • Velocity varies during race
    • Slow at start (0-40m)
    • Fastest in middle
    • Decrease from 60-100m
    • Why?
      • Energy sources- PC system 6 seconds
      • Lactate system is slower hence deceleration
  • 15. Velocity/time graphs Velocity Time Velocity changes
  • 16. Acceleration
    • Average velocity changes
    • Change in velocity over a period of time is called
    acceleration final velocity – initial velocity time taken Acceleration =
  • 17. Velocity Time On a velocity-time graph acceleration is shown by the of the line steepness (gradient)
  • 18. Velocity Time Highest acceleration? zero acceleration? deceleration?
  • 19. Vectors and scalars
    • Displacement, velocity and acceleration have direction as well as magnitude =
    • Temperature, time, speed, etc do not have direction =
    vectors scalars
  • 20. Typical question
    • The Figure shows a velocity/time graph for an elite 100-metre runner.
    (i) Use the figure to determine the velocity of the sprinter after 3 seconds, and identify the period of time when the sprinter’s acceleration was the greatest. (2 marks) (ii) What is happening to the sprinter between 6 and 11 seconds? Explain why this occurs. (3 marks)
  • 21. Answer
    • (i)
    • 1. 9.1 ms-1 (accept 9.0-9.2);
    • 2. 0-1 seconds/s. 2 marks
    • (ii)
    • 1. Deceleration/decrease in velocity; (Do not credit slowing down)
    • 2. Lack of ATP;
    • 3. CP breakdown to ATP slowing/limiting;
    • 4. Due to lack of stored PC;
    • 5. Change to slower lactic acid/alactic/anaerobic system max3 marks
  • 22.
    • From a sport of your choice:
    • Identify 2 examples of when a body’s state of motion gets quicker
    • Identify 2 examples of when a body’s state of motion gets slower
    • What causes these changes in speed and direction?
  • 23.
    • There are 2 types of force
      • Internal and external
    • Internal – contraction of muscles
    • External – air resistance, gravity and friction
    • Forces are Vectors so have
      • Magnitude and direction and are represented by arrows
  • 24. External forces
    • Gravity - force pulls objects back down to earth
    • Friction – objects moving against each other in opposition cause friction. Basketball shoes have ‘extra grip’ which actually means more friction whereas ice skates are designed for minimal friction
    • Air resistance – friction caused by air moving over a surface. Very different to wind resistance
    • Inertia – the reluctance to change state of motion. Pushing a car is hard at first but not too hard once its moving. Once moving though it would be difficult to stop!
  • 25. Newton’s Laws
    • An exam question on these is extremely straight forward once you have a basic understanding of how they apply to different scenarios
  • 26. Newton’s 1 st Law
    • The Law of Inertia
      • “ a body will remain in it’s state of motion/rest until affected by a force acting upon it”
    • A body will be reluctant to change its state of motion
    • Applying the law:
    • A football being kicked, a sprinter in the start blocks and a snooker ball prior to being hit
  • 27. Momentum
    • Every moving object has mass and velocity
    • Momentum = mass x velocity
    • If two rugby players with same mass collide, the one with higher velocity wins
    • If they have same velocity, the one with larger mass wins
    • Both have larger momentum
  • 28. Newton’s 2 nd Law
    • The Law of Acceleration
    • “ The rate of change of momentum is directly proportional to the force causing the change, and the change takes place in the direction in which the force was applied”
    • In sport, mass remains constant and so momentum equates to acceleration
  • 29. Applying the 2 nd Law
    • The magnitude and direction of the force applied by the sprinter in the blocks will determine the magnitude and direction of the force received (acceleration)
    • Acceleration is proportional to force applied (F=ma)
  • 30. Newton’s 3 rd Law
    • The Law of reaction
      • “ for every action there is an opposite and equal action force”
    • In sport this is usually the performer and the ground
  • 31. Applying Newton’s 3 rd Law
    • The performer cannot move the earth but receives significant acceleration
    • This is called Ground Reaction Force
    Action force of muscle contraction Equal and opposite force
  • 32. Using Newton’s Laws explain how an athlete accelerates out of the blocks at the start of a race.
    • The athlete remains at constant velocity, at rest, in his blocks at the start of a race due to Newton’s First Law – the Law of Inertia. In order for him to accelerate an external force must be applied.
    • As the athlete uses his muscles to generate a force into the blocks/ground there will be an equal an opposite reaction force pushing him forwards, due to Newton’s Third Law – the Action-Reaction Law.
    • This resultant force is the external force required to overcome the inertia (Newton’s 1st Law) and the athlete accelerates from the blocks.
    • The acceleration of the athlete is in direct proportion to the size of the resultant external force due to Newton’s Second Law – the Law of Acceleration. The acceleration can be calculated using the formula F=ma.
  • 33. Forces in running
    • List as many forces as you can think of acting upon the runner in the next picture
    • Label the force arrow to show the direction of the force
  • 34. Forces acting on a sprinter Action force of muscular contraction Friction Gravity Air resistance Equal and opposite Ground Reaction Force
  • 35. Forces in high jumping
    • List as many forces as you can think of acting upon the jumper in the next picture
    • Label the force arrow to show the direction of the force
  • 36.
    • Muscle force applied to ground on take off
    • Large vertical ground reaction force
    • Gravity
    • Friction between foot and ground
    • Air resistance to forward motion
  • 37. Forces in kicking
    • Explain how Newton’s 3 laws will affect the ball when it is kicked
    • Label the force arrow to show the direction of the force
  • 38.
    • 1 st Law – ball is kicked, overcomes inertia and accelerates
    • 2 nd Law – size and direction of acceleration depend on size and direction of the applied force
    • 3 rd when ball is kicked a fore equal to the force applied to the ball is felt by the foot
    • Gravity and friction slow ball down
  • 39. Typical question
    • Use Newton’s Three Laws of Motion to explain how a tennis player moves towards the ball in preparation to play a stroke. (5 marks)
  • 40. Answer
    • First Law – reluctance to change state of motion/constant motion/ uniform motion/velocity;
    • Force required to change state of motion/overcome inertia of player;
    • Muscle contractions; (Sub max 2 marks)
    • Second Law – magnitude/size of force governs change in momentum;
    • Mass remains constant;
    • Force governs magnitude of acceleration given to player;
    • And direction; (Sub max 2 marks)
    • Third Law – equal and opposite reaction force;
    • Force applied to ground/ moves performer;
    • Ground Reaction Force. (Sub max 2 marks)
    • Max of 5 marks
    • Do not credit Force = Mass x Acceleration
    • Only credit responses that relate to the player not the ball.