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.
Today we will:
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)
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 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
This is where two or more substances rub together
Friction can be an advantage in some activities and a disadvantage in other activities
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.
Which two substances are creating resistance as an advantage in these pictures?
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
How could the cyclist in this picture
reduce the effect of the wind
resistance against him?
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.
hockey drive and tennis serve.