Mechanics of movementVectors and scalars; velocity,

accelerationMomentum/impulse in sprintingNewton’s Laws applied to

movementsApplication of forces in sporting

activities

Velocity during a 100m sprint

Timing point (displacement in

Distance covere

Time to reach this

Time taken for this

Average velocity for each 10m section =

metres) d (Metres)

point (seconds)

10m section (seconds)

displacement/time (ms)

Start 0 0 0 0/0 = 0

10 10

20 10

30 10

40 10

50 10

60 10

70 10

80 10

90 10

100 10

Plot your velocity/displacement graphNow mark on your graph where the runner is at their highest acceleration, zero acceleration and when they are decelerating

(i) Use the figure to determine the velocity of the sprinter after 3 seconds, and identify the period of time when the sprinter’s acceleration was the greatest.(2 marks)

(ii)What is happening to the sprinter between 6 and 11 seconds? Explain why this occurs. (3 marks)

Acceleration

Vectors and Scalars

Provide a definition and state whether it is a vector or a scalar

Term Definition

Vector or

scalar?

Displacement

Velocity

Acceleration

Vector

Scalar

Deceleration

Speed

External Forces

Newton’s 1st Law

Newton’s 2nd Law

Newton’s 3rd Law

Using Newton’s 3 laws in a sporting situation

You are going to explain Newton’s laws and their application to sporting situations. Your partner will mark your explanation based upon the accuracy of your presentation.

Attempt 1

Attempt 2

Attempt 3

The 1st Law of Inertia“ a body will remain in it’s state of motion/rest until affected by a force acting upon it”

An example: A football being kicked, a sprinter in the start blocks and a snooker ball prior to being hitEvery moving object has mass and velocityMomentum = mass x velocityThe 2nd Law of Acceleration“The rate of change of momentum is directly proportional to the force causing the change, and the change takes place in the direction in which the force was applied”In sport, mass remains constant and so momentum equates to accelerationExample: The magnitude and direction of the force applied by the sprinter in the blocks will determine the magnitude and direction of the force received (acceleration)The 3rd Law of reaction“for every action there is an opposite and equal action force”In sport this is usually the performer and the groundThe performer cannot move the earth but receives significant accelerationThis is called Ground Reaction Force

Full example from sprintingThe athlete remains at constant velocity, at rest, in his blocks at the start of a race due to Newton’s First Law – the Law of Inertia. In order for him to accelerate an external force must be applied. As the athlete uses his muscles to generate a force into the blocks/ground there will be an equal an opposite reaction force pushing him forwards, due to Newton’s Third Law – the Action-Reaction Law.This resultant force is the external force required to overcome the inertia (Newton’s 1st Law) and the athlete accelerates from the blocks.The acceleration of the athlete is in direct proportion to the size of the resultant external force due to Newton’s Second Law – the Law of Acceleration. The acceleration can be calculated using the formula F=ma.

Forces in running

Forces in high jumping

Forces kicking a ball

Use Newton’s Three Laws of Motion to explain how a tennis player moves towards the ball in preparation to play a stroke (5 marks)

Jan 05 Question 4(b) Figure 2 shows a velocity/time graph for an elite 100-metre runner.

Figure 2(i) Use Figure 2 to determine the velocity of the sprinter after 3

seconds, and identify the period of time when the sprinter’s acceleration was the greatest. (2 marks)

Jan 07 Qu 3Elite sports performers need to develop power of both the body and the mind in order to be successful. The major leg muscles used in the drive phase of sprinting are the gastrocnemius, quadriceps, gluteals and hamstrings. Exactly the same muscles groups are also used in high jumping.

(a)Explain, using the idea of vectors, how these same muscle groups can produce both maximal horizontal motion and maximal vertical motion. (5 marks)

Jun 2002 Qu 2(a) Figure 2 shows performers bout to start a swimming race. Use this situation to

explain Newton’s three Laws of motion. (6

marks)

Jun 2003 Qu 5

(c) Figure 5 identifies the changes in horizontal linear velocity experienced by a puck that has been struck by an ice hockey stick and then collides with, and rebounds from, the end wall.

Describe and explain the horizontal motion of the puck associated with each of the time periods identified as A, B, C, D and E in the graph.

(7 marks)

Jan 05 Question 4

(c) Identify the forces A-E in Figure 3 that act on the sprinter during a race. (3 marks)