Newtons Laws

  • Key Knowledge

    • Biomechanical principles for the analysis of human movement:

    • Newton’s three laws of linear motion:

      • Inertia

      • Acceleration

      • Action-Reaction

  • Key Skills

    • Analyse, interpret and apply graphical, visual, and physical representations of biomechanical principles to improve movement skills.

DEEP

  • When answering questions, engage in a thorough approach:

    1. Definition - A straightforward statement of the concept.

    2. Equation - Present any applicable formulas.

    3. Explanation - Elaborate the concept in detail.

    4. Performance Link - Discuss the impact on performance (positive or negative).

Newton’s Laws of Motion

First Law - Law of Inertia

  • Definition:

    • A body will remain at rest or in uniform motion unless acted upon by an external force.

    • Heavier objects possess more inertia.

Application of the First Law

  • Example - Free Throw in Basketball:

    • Newton’s First Law indicates that the basketball will not move from the player’s hands unless a force (exerted by the player's muscles) acts upon it to shoot the ball.

Second Law - Law of Acceleration

  • Definition:

    • The force applied to an object will produce acceleration in the direction of the force, directly proportional to the size of the force, and inversely proportional to its mass.

  • Equation:

    • F=mass⋅accelerationF=mass\cdot acceleration

  • In Practice:

    • A lighter object will accelerate faster when the same force is applied.

    • Comparisons:

      • Table tennis ball vs tennis ball vs netball vs shot put.

      • Lighter athletes vs heavier athletes.

    • Concepts:

    • Inversely Proportional: As one increases, the other decreases (More mass = less acceleration).

    • Directly Proportional: As one increases, the other does as well (More force = more acceleration).

Application of the Second Law

  • Example - Cyclists Acceleration:

    • If two cyclists have the same overall force but one cyclist accelerates away, the one accelerating has a smaller mass.

  • Sample Question - Comparing Acceleration:

    • When two athletes apply the same force to starting blocks, the one with the smaller mass accelerates faster than the heavier athlete.

Third Law - Action-Reaction

  • Definition:

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

    • This indicates that when one body applies a force on a second body, the second body responds with an equal force in the opposite direction on the first body.

Application of the Third Law

  • Example - Starting Blocks:

    • Utilizing starting blocks, when an action force is applied into the blocks, the reaction force acts in the opposite direction and propels the runner more effectively toward their goal, resulting in a faster start and potentially quicker finishing time.

Summary of Newton's Laws

  1. First Law: A body will remain at rest unless acted upon by an external force.

  2. Second Law: A force applied to an object will produce a change in motion (acceleration) directly in the direction of the force, proportionate to the force size.

  3. Third Law: For every action, there is an equal and opposite reaction.