LEARNING TO LIVE WITH LAWS OF MOTION .pptx

CLASS 11 PHYSICS PPT

1. LEARNING TO LIVE WITH LAWS OF MOTION BY: PRAVEEN DHINGRA

2. INTRODUCTION Aristotle famously represented a force as anything that causes an object to undergo “unnatural motion”. Sir Isaac Newton was one of the first scientists to study gravity and force. Any kind of force is just a push or a pull. It can be described as a push or pull on an object.

3. EFFECTS OF FORCE In the field of physics, motion is characterized as the alteration in position over a given period. Put simply, motion pertains to the displacement of an object. Generally, motion can be categorized as: 1. Alteration in velocity 2. Modification in trajectory The Force produces various outcomes, and here are a few examples: 1. Force can initiate the movement of an object that is initially stationary. 2. It has the ability to impede or decelerate the progress of a moving object. 3. It can enhance the velocity of an object in motion. 4. Additionally, it can induce alterations in the path, shape, and size of a moving object.

4. NEWTON’S LAWS OF MOTION

5. Newton's laws of motion are a set of three fundamental laws that form the basis of kinematics, the study of motion. These laws establish a connection between the motion of an object and the forces acting upon it. Isaac Newton, the renowned physicist, was responsible for formulating and introducing these laws. He utilized them to elucidate numerous physical systems and phenomena. Newton's publication of these laws in 1687 marked a significant milestone in the development of classical mechanics. By employing these laws, Newton was able to investigate and provide explanations for a wide range of physical phenomena. Moreover, he demonstrated that these laws, along with the law of universal gravitation, could account for Kepler's laws of planetary motion. Even today, Newton's laws of motion remain among the most pivotal and influential principles in the field of physics.

6. NEWTON’S FIRST LAW OF MOTION The initial law formulated by Newton asserts that any object will persist in a state of rest or uniform motion in a straight path, unless an external force compels it to alter its state. This inherent resistance to changes in motion is known as inertia.

7. NEWTON’S SECOND LAW OF MOTION Newton's second law, expressed as F = ma, provides a numerical explanation of the effects a force can have on the movement of an object. This law states that the rate at which an object's momentum changes over time is directly proportional to the force exerted on it, with both the magnitude and direction being equal.

8. NEWTON’S THIRD LAW OF MOTION Newton's Third Law of Motion: Action and Reaction In accordance with Newton's third law, it is posited that in nature, every action or force has a corresponding reaction that is equal in magnitude and opposite in direction. When object A applies a force upon object B, object B will exert an equal and opposite force upon object A. In essence, forces arise from interactions between objects.

9. EVERYDAY PHENOMENA WITH NEWTON’S LAWS OF MOTION

10. Real Life Examples of Newton’s First Law (inertia) The electric fan continues to move for a period after the electricity is turned off. F all back forward when the stationary bus starts to move.

11. Car Airbags: The purpose of the airbag is to expand during a collision and safeguard the driver's head from colliding with the windshield. In the event of an accident involving a car equipped with an airbag, the abrupt deceleration triggers an electrical switch, initiating a chemical reaction which generates a gas to fill the airbag and shield the driver's head. The book resting on the table remains stationary until it is disturbed The flow of blood from your head to your feet halts abruptly when you descend in an elevator.

12. By striking the bottom of the wooden handle against a solid surface, the hammerhead can be securely tightened. When encountering a sudden obstruction such as a sidewalk, rock, or any other obstacle that abruptly halts the skateboard, you propel forward and separate from the board while riding. Explanation of aircraft motion in response to throttle adjustments made by the pilot.

13. Real Life Examples of Newton’s Second Law Newton's second law of motion finds its practical applications in our everyday lives when we attempt to manipulate objects. For instance, halting a rolling ball or initiating its movement by giving it a push. In the realm of car racing, reducing the weight of the vehicles becomes crucial to enhance their speed. Engineers strive to minimize the mass of racing cars as it directly influences acceleration. A lower mass enables higher acceleration, thereby increasing the chances of winning the race.

14. When we kick a ball, we exert force in a specific direction, which determines the ball's subsequent movement. Furthermore, the magnitude of force applied to the ball directly correlates with how forcefully we kick it, resulting in the ball traveling a greater distance. When it comes to pushing a cart, it is noticeably easier to maneuver an empty one compared to a fully loaded one. The greater the mass, the more power is required to accelerate the cart. Among two individuals walking, the one with a higher weight will generally move at a slower pace. This is because the lighter individual experiences a greater acceleration in comparison.

15. Engineers apply Newton’s third law when they design rockets and other devices. For example, the rush of gases upward from the rocket when it ignites causes it to increase its speed. When a man runs, he strongly influences the earth and the earth also strongly influences him, so that both the earth and the man influence each other. When you jump, your feet exert a force on the ground and the earth exerts an equal and opposite reaction force that pushes you into the air. Real Life Examples of Newton’s Third Law

16. When a person is in the water, the water pushes the person forward while the person pushes the water back, both act on each other. Helicopters create lift by pushing the air downwards, subjecting it to an upward reaction force. Birds and aeroplanes also fly by exerting a force on the air that is opposite to the force required. For example, the bird's wings push the air back and forth to lift the movement forward.