Quick Questions What is moment of inertia What

Quick Questions • • What is moment of inertia? What affects moment of inertia? What is Angular motion measured in? What is angular momentum affected by?

Biomechanics Biomechanical Principles - Projectile Motion

Learning Objectives Learning Objective: Understand the what affects the flight of a projectile in motion - free body diagrams, resolution of forces, flight paths, Bernoulli’s principle, Magnus force All – describe how factors affect distance travelled of a projectile - Draw free body diagrams on a projectile in flight (W & AR) Most – describe the effects of the parallelogram of forces acting on a projectile in flight - Some – apply bernoulli’s principle to a discus, javelin, ski jumper, f 1 car and track cyclist. - apply theory of magnus force to deviations in flight patterns Few – use their knowledge to explain the flight patterns of projectiles and how athletes can use their knowledge to maximise their performance

Free body diagrams (W & AR) • Shuttlecock • Javelin • Shot put See book 2 pages 99 - 100

FBD of a shuttle cock Size of AR decreases as velocity is reduced, which has been caused by the AR. AR W AR force is small as shuttle has slowed. Weight force remains the same throughout and is now larger than AR, resulting in the shuttle dropping. AR W AR is much larger than W as the velocity of shuttle is high as it leaves the racket head. W AR

Factors affecting horizontal distance travelled by a projectile • Height • Speed • Angle of release ? How do you think each of these affect the distance travelled ?

Resolution of forces acting on a projectile in flight using the parallelogram of forces See book 2 pages 98 – 103 To consider the result of all forces acting on a projectile in flight a parallelogram of forces can be drawn This shows the resultant force acting on a projectile (sum of all forces / net force) W AR Resultant Force

Patterns of flight paths parabolic non-parabolic http: //www. splung. com/content/sid/2/page/projectiles - parabolic flight pattern – affected by angle (cannonball) http: //bmsi. ru/doc/cfa 29448 -8286 -437 b-bc 88 -f 2710 d 2 f 55 a 6 - graphs showing flight paths of a javelin thrown at different release angles and speeds

Spin • Magnus Effect https: //www. youtube. com/watch? v=NWku. OY-XNt 8 – Roberto Carlos Free Kick https: //www. youtube. com/watch? v=m 57 cimn. J 7 fc – Football physics – the ‘impossible’ free kick https: //www. youtube. com/watch? v=O 2 vr. Vwjqktg – Killerspin Table Tennis Technique: ball and spin https: //www. youtube. com/watch? v=hg. HC 2 zm. Os. AI – side/back spin Table Tennis Serve Tutorial Athletics Engineered: How a Curveball Curves https: //www. youtube. com/watch? v=DGNt. P 64 m 8 DA&safe=active What is magnus force - https: //www. youtube. com/watch? v=23 f 1 jv. GUWJs The magnus effect explained - https: //www. youtube. com/watch? v=8 k. Vu. KAqy_2 k

Take notes and Draw diagrams showing the effects of spin (from books) • Top spin • Back spin • Side spin You must show - Direction of motion - Direction of spin - Direction of airflow - Where the air is at higher and lower pressure

Side Spin

Exam Questions • June 2011 - 4 b) Explain how a performer generates spin on a ball and describe the effects of spin on the bounce of a ball. (5) • Jan 2012 - 4 c) Explain how a lift force is imparted to a discus during flight and describe its effects on the flight path of the discus. (6) • June 2014 - 4 c) Describe the effect of topspin on the flight path of a ball. Explain the effect that topspin has on the bounce of a ball. (5)

Exam Questions • Jan 2011 - 4 c) Use a diagram to work out the resultant force acting on a hard hit badminton shuttle during the early stages of the flight path of a long serve. Explain the effect of the resultant force acting on the flight path of the shuttle. (5) • June 2010 - 4 c) Compare the shape of the flight path of a shot putt with that of a fast moving badminton shuttle. Explain the reasons for the differences in their respective flight paths. (4) • Jan 2010 - 4 d) Sketch a free body diagram to show the forces acting on a ball with topspin during flight. Examine the effects of different types of spin on a ball during flight and when bouncing. Evaluate the advantages and disadvantages of each type of spin in sport. (20)