1. Biomechanics • Mechanics of movement:
– vectors and scalars – velocity, acceleration and
momentum/impulse in sprinting
– Newton’s Laws applied to movements –
application of forces in sporting activities
– projectile motion – factors affecting distance,
vector components of parabolic flight
– angular motion – conservation of angular
momentum during flight, moment of inertia
and its relationship with angular velocity.
– vectors and scalars – velocity, acceleration and
momentum/impulse in sprinting

2. Recap: Inertia
Inertia is the reluctance of a body to move or change its state of motion
Objects will stay in their state of inertia (i.e. stationary or moving at a constant velocity) unless a force overcomes that inertia.
The inertia of a body is directly proportional to its mass
Therefore an object with a greater mass requires a larger force to overcome its inertia and change its state of motion.

3. Recap: Momentum Momentum is the amount of motion a body has
Momentum is calculated as:
Mo = Mass (kg) x Velocity (ms-1)
The more massive, or the faster an object, the more momentum it has.
Momentum is linked to inertia – the more momentum something has, the harder it is to stop!

4. What is each of their momemtum when running at 4ms-1
Ben Morgan
1m 93
117 kg
Richie Gray
2m 08cm
120 kg
Leigh Halfpenny
1m 78cm
83 kg
What is each of their momemtum when running at 4ms-1

5. Impact
Momentum becomes more important in sporting situations where collisions or impacts occur.
The outcome of a collision depends largely on the momentum of each of the colliding bodies.

6. Impulse = Ft = Change in momentum
The change in momentum during a collision depends on the ‘impulse’ of an impact
The impulse is the force that is applied multiplied by the time its applied for
Impulse = F x t or Ft
The force applied and the time it is applied for determines the change in momentum of an object.
Therefore…
Impulse = Ft = Change in momentum

7. Impulse
So… this means that an increase in the force applied, or an increase in the time its applied will result in a GREATER change in momentum
Equally…
… for the same change in momentum, if it occurs over a longer period of time, the force required will be less.
Change in Momentum = F x T

8. Examples of using impulse to change momentum in sport:
Cricket
Hockey:

9. Examples of using impulse to change momentum in sport:
Shot put:
Gymnastics

10. What’s being shown in this diagram?

12. Which impulse would make the athlete accelerate?
Impulses can be shown as force – time graphs
Both these impulses are made as a result of an athlete landing and then pushing off from one foot during a sprint.
Which impulse would make the athlete accelerate?
Force (N)
If the force is positive, it causes the athlete to accelerate
Time (s)
If the force is negative, it causes the athlete to decelerate
The longer the force is applied for, the bigger the impulse (change in momentum)
The area under (or over) the line is equivalent to F x t = the impulse

13. Impulse
Area 2 – Represents the impulse of a body due to the ground reaction force – it’s a positive impulse
Area 1 – represents the impulse of a body landing on the ground – it’s a negative impulse

14. Impulse
Small –ve and large +ve impulse – shows a body that is accelerating e.g. High jumper
Large –ve and small +ve impulse – shows a body that is decelerating e.g. volleyball player landing
+ve and –ve are equal – shows a runner travelling at a constant speed

15. Exam Qu
The following force–time graphs were obtained during the various stages of a runner’s 100-metre sprint.
Using Figure 6, identify which graph is associated with each of the following phases of a 100-metre sprint, giving reasons for your answers:
(i) early in the sprint;
(ii) during the middle part of the sprint; and
(iii) towards the end of the sprint.
(6 marks)

17. X = a foot contact in the middle of a sprint
Y = a point where the athlete is just pushing on the ground at the start of a sprint
Z = a foot contact just after the player has begun sprinting

18. Equation You Say We Pay
Speed

19. Equation You Say We Pay
Acceleration

20. Equation You Say We Pay
Impulse

21. Equation You Say We Pay
Weight

22. Equation You Say We Pay
Momentum

23. Equation You Say We Pay
Velocity

24. Equation You Say We Pay
Change in Momentum