L03- Newton's Laws of Motion-Learn

Page 1: Biomechanics Overview

• Linear Kinetics: Study of forces and motion in biomechanics.

• Newton's Laws of Motion: Fundamental principles governing movement.

• Gravity: The force that attracts two bodies toward each other.

Page 2: Lecture Outline

• Newton’s Laws:

  • 1st Law: Law of Inertia

  • 2nd Law: Law of Acceleration

  • 3rd Law: Law of Action-Reaction

  • Law of Universal Gravitation

  • Centre of Mass/Gravity

Page 3: Newton’s Laws of Motion

• Kinematics: Motion in terms of time and space (velocity, distance, acceleration).

• Kinetics: Forces acting on a body/system and motion production.

• Newton’s Contributions: Formulated in his 20s; pivotal for biomechanics and sports.

• Sir Isaac Newton: Key figure (1642-1727) in physics and mathematics.

Page 4: Newton’s 1st Law: Law of Inertia

• Definition: A body remains at rest or continues with constant velocity unless acted upon by an external force.

• Concept of NET force: Important to understand vector components.

Page 5: Newton’s 1st Law: Example

• Force Scenarios:

  • If F1 = F2: No movement

  • If F1 > F2: Movement in the direction of F1

  • If F1 < F2: Movement in the direction of F2

  • Different angles affect direction and magnitude.

Page 6: Applicability in Sports

• Long Jump Example: Discusses inertia in a sporting context.

Page 7: Net Force Implications

• Rest and Motion: A body at rest stays at rest; a body in motion remains in motion if no net force acts.

• Examples: Everyday and sports-related situations.

Page 8: Newton’s 2nd Law: Law of Acceleration

• Definition: Acceleration is proportional to the force acting on an object, F = ma.

• Units: F (N), m (kg), a (m/sec²).

• Newton’s Constant: 1 N accelerates 1 kg at 1 m/sec².

Page 9: Understanding F = ma

• Acceleration Calculation: a = F/m; greater mass requires greater force for acceleration.

• Force and Acceleration Relationship: Increasing force increases acceleration.

Page 10: Newton’s 3rd Law – Action-Reaction

• Definition: Every action has an equal and opposite reaction force.

• Significance: Reaction forces are essential to change motion.

Page 11: Implications for Sport

• Ground Reaction Forces: Importance of body positioning to maximize these forces.

Page 12: Practical Example in an Elevator

• Experiencing Motion: How a biomechanist would notice elevator movement without sight.

Page 13: Forces in Elevator Scenarios

• Force Dynamics: Examine forces acting on a person in an elevator and their perceptions.

Page 14: Newton's Law of Gravitation

• Gravity Basics: Essential understanding of gravitational forces.

Page 15: Law of Gravitation Formula

• Attractive Force: F = G (m1m2)/r²; effects of distance and masses.

• Practical Example: Very small forces between small masses.

Page 16: Weight Calculation on Earth

• Weight Equation: W = G (mearth × mobject)/r²; results in fixed gravitational acceleration g = 9.81 m/sec².

Page 17: Trivia of the Day

• Earth's Gravitational Differences: Discussion on equator vs. poles.

Page 18: Additional Facts

Page 19: Calculating Gravity Above Earth

• Gravity at 1000 km: Adjusted calculations based on distance from Earth's center.

Page 20: Inertia in Linear Motion

• Definition: Inertia as resistance to motion changes, linked to mass.

Page 21: Weight and Centre of Gravity

• Weight Definition: Sum of attractive forces acting towards Earth's center (W = mg).

• Centre of Gravity: Resultant force concept central to biomechanics.

Page 22: Centre of Gravity Insights

• CG Positioning: Can lie outside physical boundaries; implications for sports.

Page 23: Weight on Moon

• Weight Calculation: Changes in weight versus mass on the moon (gravity = 1.57 m/s²).

Page 24: Upcoming Test Reminder

• Online Class Test: Details about the formative assessment based on weeks 1-3 content.