GCSE - Physical Education - Chp 5 - Anatomy and Physiology - Simple Biomechanics

• Physical education
• Secondary Education

Chp 5 - Simple Biomechanics 

Anatomy and Physiology 

Learning objectives

 

1) Identify what is meant by force.

 2) Understand and apply the equation involving force, mass and acceleration.

 3) Describe the effects force has on aspects of sports performance.

What you need to know.. 

'Specification'

Specification Link

https://www.cambridgeinternational.org/Images/555751-2022-2024-syllabus.pdf

What comes to mind when you think of the term 'Force'?

Definition.. 

A force is, “a push or a pulling action applied upon an object. Measured in Newtons (N)”

Definition means we must know it off by heart for your exam. 

Issac Newton

How can forces be applied within sport?

Force can be applied in large quantities:

A rugby player making a tackle

A sprinter driving out of the blocks

Force can be used in a more controlled way:

A golfer playing a chip onto the green

A badminton player playing a delicate drop-shot

Force can be a push or a pull:

Pushing against the opposition when scrummaging in rugby

Pulling the oars when rowing

Newtons first law of motion. 

A body continues in a state of rest or uniform velocity unless acted upon by an external or unbalanced force.

The law of inertia 

Inertia – “The resistance of an object to changes in motion”

According to the law of inertia, force is required to cause:

1. A stationary object / body to move
2. A moving object / body to change direction, accelerate or decelerate
3. An object / body to change shape

A force can cause a stationary object to move

 A force can cause a moving object to change direction

A force can cause a moving object to accelerate

A force can cause a moving object to decelerate

A force can cause an object to change shape

Task – provide examples from a sport of your choice to explain each effect of force

Newton’s second law of motion

“When a force acts on an object, the rate of change of momentum experienced by the object is proportional to the size of the force and takes place in the direction in which the force acts.”

The law of acceleration

 

The law of acceleration can be explained by the formula – 

force (N) = mass (kg) x acceleration (m/s2)

• The greater the force applied, the greater the acceleration
• The greater the mass, the slower the object / body accelerates

F = MA

Mass – “The quantity of matter in a body (kg)”

Acceleration – “The rate at which an object changes speed (m/s2)”

Exam style questions...

A ball is kicked and accelerates at 10m/s2, it has a mass of 0.5kg. How much force is applied to the ball?

A sprinter weighing 90kg accelerates out of the blocks at 3m/s2. How much force does the sprinter apply against the starting blocks?

A tennis ball with a mass of 0.1kg is hit with a force of 200N. How quickly does the ball accelerate?

What happens to the body or object if applied force is reduced? (e.g. a 400m runner begins to fatigue on the final straight)

Newton’s third law of motion

"For every action, there is an equal and opposite reaction."

The law of action and reaction

 

When a sprinter drives out of the blocks at the start of a race - 

Their muscles exert a force of 200N against the starting blocks (downwards and backwards)

The starting blocks exert an equal force of 200N in the opposite direction to the force applied by the sprinter (upwards and forwards)

This reaction force propels the sprinter from the blocks

If the sprinter has a mass of 80kg, how fast to they accelerate from the starting blocks?

Summary extension questions..

1) State the equation used to calculate force

2) If a sprinter increases the force they apply to the track, what will increase?

3) Provide an example of a push and a pull force in sport

4) A footballer kicks a football weighing 1kg with a force of 25N. Calculate the acceleration of the ball

5) A tennis ball weighing 0.1kg accelerates at 400m/s2 when served. How much force was applied to the ball?

6) Define Newtons third law of motion. 

Topic summary definitions.

A force - “a push or a pulling action applied upon an object. Measured in Newtons (N)”

First law of motion -  "A body continues in a state of rest or uniform velocity unless acted upon by an external or unbalanced force."

Inertia – “The resistance of an object to changes in motion”

Second law of motion - “When a force acts on an object, the rate of change of momentum experienced by the object is proportional to the size of the force and takes place in the direction in which the force acts.”

Third law of motion - "For every action, there is an equal and opposite reaction."