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Mechanical principles: Streamlining Levers Force Friction Resistance. Standard Grade PE Skills & Techniques. Learning Outcomes. Today we will: Learn about the mechanical principles in PE Revise some of the previous topics in Skills & Techniques. . Force.
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Mechanical principles: Streamlining Levers Force Friction Resistance Standard Grade PESkills & Techniques
Learning Outcomes Today we will: • Learn about the mechanical principles in PE • Revise some of the previous topics in Skills & Techniques.
Force The muscles create force. The faster the muscle contraction, the greater the force For every action, there is an equal and opposite reaction (Newton’s third law)
Force When performing skills different forces are applied: E.g. when a sprinter pushes back against the blocks this will propel him forwards – the harder he pushes, the faster he will go forwards. In volleyball, a spiker pushes hard against the floor to propel them upwards as high as possible to make the spike easier.
Force Force can also be in the same direction as the movement……. E.g. a shot putter’s direction of force is forwards and upwards to try to create an optimum angle to propel the shot at maximum distance A badminton player would apply force forwards and downwards in a smash
Force • Look at the pictures below. Which direction will the force be applied when performing this skill?
Friction This is where two or more substances rub together Friction can be an advantage in some activities and a disadvantage in other activities
Friction as an advantage Footballers wear studs to increase the friction between them and the ground. This helps them to change direction and run faster. Creating more friction between the arms and the water in swimming helps you to swim faster. Having a longer arm pull in the water helps push back more water, thus helping you to swim faster.
Friction / Resistance Which two substances are creating resistance as an advantage in these pictures?
Friction as a disadvantage In swimming friction between your body and the water slows you down. Therefore you need to get streamlined in the water to cut down friction. In football during windy conditions friction between the ball and the wind will slow the ball down In skiing, the skiers wear tight clothing to cut down the resistance between the air and their body to help them ski faster
Reducing resistance? How could the cyclist in this picture reduce the effect of the wind resistance against him?
Streamlining • Trying to cut down the resistance between your body and the air or water depending on the activity. e.g. in skiing competitors wear tight fitting clothes to cut down on air resistance. in swimming competitors try and get flat in the water to cut down resistance between their body and the water.
Streamlining • Why might this cyclist wear a helmet like the one in the picture?
Levers • The longer the lever the faster will be the speed at its end. • The shorter the lever the greater the accuracy.
Long Levers • Some activities use long levers to generate speed/power. • e.g. in badminton you would use a long lever, a straight arm at impact, in a clear or smash to generate power making the shuttle go faster or further making it more difficult to return. • In golf you generally use a driver (the longest club) to hit the ball the greatest distance. By using this club along with straightening your arms at impact create the longest lever possible, generating more speed in the club face, helping hit the ball the longest distance. • Other skills using long levers? • Javelin throwing, football shot from distance, hockey drive and tennis serve.
Short Levers • Some activities short levers are used to give accuracy to the shot. • In Badminton in a short serve you would bend your arm to hit the shuttle less hard but more accurately. • In football when you are passing the ball using a side foot pass you bend your leg take short swing and look to hit the ball accurately a short distance.
