Author: USER
Company: BHASVIC

Biomechanics short Test for AS                                 DTA

Progress test on Biomechanics
Example of free flow diagram

.	Sketch a free body diagram to show the forces acting on a sprinter immediately after the start of a 100m race.
	Comment on the respective sizes of the horizontal forces in relation to the resulting motion.
	1 mark per point max 4:

	1 mark for free body diagram:
		
	3 marks for 3 of:
•	friction force/F is greater than the air resistance/F > AR;
•	friction force/F is large due to the large force being exerted on the ground by the sprinter/running spikes;
•	air resistance/AR is relatively small due to small cross sectional area/relatively low velocity/tight fitting clothing;
•	net/resultant force acts in the same direction as friction/forward direction causing acceleration;
•	link with Newton’s 1st Law;
•	the greater the friction force the greater the acceleration in the early stages of the race;
•	link with Newton’s 2nd Law.
[4]

1.	The figure below shows a hockey player taking a penalty flick at goal. 

Sketch a free body diagram showing all the forces acting on the hockey ball as it is being flicked. 
Using Newton’s Laws of Motion, explain the effect of the resultant force acting on the hockey ball.
[6]
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3.	The figure below shows a gymnast performing a headstand and a handstand.

	With reference to the centre of mass, explain why a headstand is an easier balance to hold than a handstand.
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[4]

 
1.	1	W/weight acting downwards from CM.
2	F/force acting from back edge of ball.
3	AR/air resistance acting in opposite direction to motion.

(Points must relate to correct law)
4	Newton 1 – The ball remains stationary until it is flicked.
5	Newton 2 – The ball will accelerate proportionately to the size of the force acting upon it/larger the force the faster/further it will go.
6	Newton 2 – The ball will accelerate in the direction of the force.
7	Newton 3 – The stick applies a force to the ball, therefore the ball applies an equal and opposite force to the stick.
[6]

2.	4 marks max:
1.	Headstand is easier to hold because of larger area of support 
2.	Headstand is easier to hold because of the three/more points of balance/
Handstand is less stable because it only has two points of balance 
3.	Centre of mass is lower in headstand therefore more stable 
4.	Centre of mass must be over base/area of support  
5.	If centre of mass moves out of area/base of support balance is lost 
[4]

Brighton Hove and Sussex Sixth Form College