Comments for Physical Education Studies Teachers' Association (PESTA) http://pesta.shimatech.com.au Promoting the teaching of Physical Education Studies (PES) and fostering the professional development of PES teachers Sun, 05 Feb 2012 07:37:27 +0800 hourly 1 http://wordpress.org/?v=3.3.2 Comment on Biomechanical principles and human motion by Van Tran http://pesta.shimatech.com.au/2012/01/26/biomechanical-principles-and-human-motion/#comment-5 Van Tran Sun, 05 Feb 2012 07:37:27 +0000 http://pesta.shimatech.com.au/?p=175#comment-5 Oh something I forgot to ask. Oh something I forgot to ask.

]]> Comment on Biomechanical principles and human motion by Peter Whipp http://pesta.shimatech.com.au/2012/01/26/biomechanical-principles-and-human-motion/#comment-4 Peter Whipp Sun, 05 Feb 2012 05:23:41 +0000 http://pesta.shimatech.com.au/?p=175#comment-4 No problem No problem

]]> Comment on Biomechanical principles and human motion by Van Tran http://pesta.shimatech.com.au/2012/01/26/biomechanical-principles-and-human-motion/#comment-3 Van Tran Sun, 05 Feb 2012 05:04:18 +0000 http://pesta.shimatech.com.au/?p=175#comment-3 Thanks for the detailed explanation Thanks for the detailed explanation

]]> Comment on Biomechanical principles and human motion by Peter Whipp http://pesta.shimatech.com.au/2012/01/26/biomechanical-principles-and-human-motion/#comment-2 Peter Whipp Sat, 04 Feb 2012 04:17:53 +0000 http://pesta.shimatech.com.au/?p=175#comment-2 The muscles in the lower limb provide force (Newton’s 2nd law) to rotate the various segments (thigh and leg). This builds linear velocity of the ankle (instep) for impact with the ball. Impact is an example of: Newton 1 – Ball will change direction Newton 2 – Acceleration of ball proportional to its mass and applied force Newton 3 – Equal and opposite force ball to foot and foot to ball Coefficient of restitution between ball-foot will determine how much momentum in the system is conserved. Remember ‘instep’ has linear momentum as does the ball – some energy ‘lost to the system’ so you have an imperfectly elastic collision. The muscles in the lower limb provide force (Newton’s 2nd law) to rotate the various segments (thigh and leg).

This builds linear velocity of the ankle (instep) for impact with the ball.

Impact is an example of:
Newton 1 – Ball will change direction
Newton 2 – Acceleration of ball proportional to its mass and applied force
Newton 3 – Equal and opposite force ball to foot and foot to ball

Coefficient of restitution between ball-foot will determine how much momentum in the system is conserved. Remember ‘instep’ has linear momentum as does the ball – some energy ‘lost to the system’ so you have an imperfectly elastic collision.

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