UNIT 1 – AREA OF STUDY 2BIOMECHANICAL MOVEMENT

PRINCIPLES

PRINCIPLES OF FORCE PRODUCTION

ULTIMATE FRISBEEThe game of Ultimate Frisbee was a challenging one and there were a number of factors that contributed to success within the game:

• Name 3 outside factors that contribute to you achieving success in a game of Ultimate Frisbee?

Answer the following questions in relation to your game of Ultimate Frisbee

What was the most difficult aspect of the game?

Does the size, shape and material of the frisbee affect the flight path?

What other factors affect the flight path of the frisbee? (refer to above question to help you)

How does the angle at which the frisbee is thrown affect its flight?

How is lift force generated in the game of Ultimate Frisbee?

CHAPTER SNAPSHOT

INERTIA# An object will remain in a state

of rest or constant motion unless acted upon by a state of force

# Inertia is a tendency for a body to resist change in its state of motion

# The amount of inertia an object has is directly related to it’s mass. The more massive an object, the greater the force needed to change it’s state of motion.

MASS AND WEIGHT MASS- Is the amount of matter that makes up an object

WEIGHT- Is the measure of gravitational force acting on a

bodyBecause the weight of something is usually given in kg they are usually referred to as the same thing. However, weight is a force that is exerted on the body by gravity. Weight can be calculated by multiplying mass x acceleration due to gravity (9.8m/s squared)Because weight is a force the units are newtons

FORCES FORCE – is a push or a pull acting on an object

In sport it is very easy to see when a force is acting

The force of gravity will pull a ball back to the ground after it is thrown

However, the effect of of a force cannot always be seen.

Record where the force is being applied in the following examples

Can you give me an example of a reaction force and explain why it cannot be seen?

EXAMPLES OF FORCE

REACTION FORCE

NEWTON’S LAWS OF MOTION Newton’s first law – law of inertia

A body will remain at rest or continue in a state of constant motion unless acted upon by an external force

A ball projected into the air will continue in a straight-line path unless acted upon by an external force – Gravity is the external force that acts to bring the ball back to earth.

Can you supply 3 more examples of the Law of Inertia in a sporting situation

NEWTON’S LAWS OF MOTION Newton’s second law – law of acceleration

A force applied to an object will produce a change in motion (acceleration) in the direction of the applied force that is directly proportional to the size of the force.

To put it simply, increased force means increased acceleration, and increased mass means decreased acceleration

This can be calculated in the following way:

F = ma

Where F is force (N), m is mass (kg) and a is acceleration (m/s squared)

NEWTON’S LAWS OF MOTION Newton’s third law – law of action-reaction

For every action there is an equal an opposite reaction In sporting situations, it is sometimes difficult to see

the reaction force. When a tennis ball is hit, the force applied by the

racquet is obvious to see as the ball changes direction and accelerates. The reaction force of the ball on the racquet is more difficult to see. This is because the racquet has a greater mass than the ball and the change in it’s acceleration is very small.

An easier way to see reaction force – medicine ball and a scooter board!!! Have fun!

TYPES OF FORCES

There are a number of different forces that act on the body such as gravity, weight, friction and air and water resistance. In sport , these forces can speed up, slow down or change direction of a ball, bat or body.

What would happen to a ball without gravity?

FRICTION

Friction is a force that occurs when two surfaces come in contact with each other. The friction force opposes the motion of an object

In sport it can be good to decrease friction between two surfaces – such as downhill skiing or bobsleigh.

It can also be good to increase the friction between the surfaces. A gymnast or weightlifter will use magnesium chalk to to increase the friction between their hands and body

FRICTION

To start an object moving across a surface, you must first overcome the friction force by applying a greater force

Can you name 2 sports where friction is reduced. Explain the method used.

Can you name 2 sports where you would try to increase friction. Explain the method that is used.

HOT HANDS – how hot can you handle?

AN EXAMPLE OF FRICTION

REVISION QUESTIONS1. Describe the two ways that a force can affect an object or body :

2. State each of Newton’s three laws and demonstrate your understanding of each law by using a sporting example:

3. Using Newton’s second law of motion, explain why a medicine ball will not move as quickly as a basketball when they are both thrown with the same force:

4. Provide three examples of action and reaction forces in sport: