Isaac Newton’s Laws of Motion

Isaac Newton’s Laws of Motion are the basic foundations of classical mechanics. These laws relate the forces that act upon a body to the motion of the body.

Newton's first law of Motion

The first law states that “An object at rest will remain at rest and an object in motion will remain in motion with the same speed and in the same direction unless acted upon by a net external force.” This law is also called as the law of inertia. This law means that a stationary object will remain stationary and not moving until a force will act upon it and a moving object will neither slow down nor move faster until an unbalanced force will act upon it. An unbalanced force or net external force is referred to as the vector sum of all forces acting on the body that is not equal to zero. As an example, consider a remote-controlled toy car. It does not move unless you attempt to move it. When it is already in motion, it moves in one direction unless you attempt to change its direction and it remains moving until you attempt to stop it.

Newton's Second law of Motion

The second law states that “The force applied to a body produces a proportional acceleration.” This law is described in the equation F=ma where F is force applied to the body, m is the mass of the body, and a is the acceleration of the body. The force applied to the body is equal to the vector sum of all  forces acting upon the body when many forces are acting upon the body in an instant. The direction of the applied force acting upon the body is the same as the direction of the acceleration of the body. This law also describes that the acceleration of the body is inversely proportional to the mass of the body. Applications of this law are easily observed in our everyday life. Consider again a toy car. When a net external force is applied to it, it accelerates but when you put something heavy on it, it needs more applied force to achieve the same acceleration. When the same force is applied on both, the one that is heavier will accelerate less.

Newton's Third law of Motion

The third law states that ''every action there is always an equal and opposite reaction.” This means that when a force is applied on an object, the object reacts with a force that is equal in magnitude to the force applied on it but it acts in the opposite direction. The force may be equal in magnitude but the acceleration of the one doing the action is not always the same as the acceleration of the one that is reacting because the mass of the two objects may not always have the same mass. Consider a jack in the box. When the top of the box is pushing the jack down, the jack is pushing the top of the box upward with the same amount of force that it is pushed by the top of the box. In the same way, when you press or push something, it will press or push you back with the same amount of force.

These three laws of motion are the basic principles in which the statics and dynamics of bodies are developed.

Isaac Newton’s Laws of Motion are the basic foundations of classical mechanics. These laws relate the forces that act upon a body to the motion of the body.

The first law states that “An object at rest will remain at rest and an object in motion will remain in motion with the same speed and in the same direction unless acted upon by a net external force.” This law is also called as the law of inertia. This law means that a stationary object will remain stationary and not moving until a force will act upon it and a moving object will neither slow down nor move faster until an unbalanced force will act upon it. An unbalanced force or net external force is referred to as the vector sum of all forces acting on the body that is not equal to zero. As an example, consider a remote-controlled toy car. It does not move unless you attempt to move it. When it is already in motion, it moves in one direction unless you attempt to change its direction and it remains moving until you attempt to stop it.

The second law states that “The force applied to a body produces a proportional acceleration.” This law is described in the equation F=ma where F is force applied to the body, m is the mass of the body, and a is the acceleration of the body. The force applied to the body is equal to the vector sum of all  forces acting upon the body when many forces are acting upon the body in an instant. The direction of the applied force acting upon the body is the same as the direction of the acceleration of the body. This law also describes that the acceleration of the body is inversely proportional to the mass of the body. Applications of this law are easily observed in our everyday life. Consider again a toy car. When a net external force is applied to it, it accelerates but when you put something heavy on it, it needs more applied force to achieve the same acceleration. When the same force is applied on both, the one that is heavier will accelerate less.

The third law states that ''every action there is always an equal and opposite reaction.” This means that when a force is applied on an object, the object reacts with a force that is equal in magnitude to the force applied on it but it acts in the opposite direction. The force may be equal in magnitude but the acceleration of the one doing the action is not always the same as the acceleration of the one that is reacting because the mass of the two objects may not always have the same mass. Consider a jack in the box. When the top of the box is pushing the jack down, the jack is pushing the top of the box upward with the same amount of force that it is pushed by the top of the box. In the same way, when you press or push something, it will press or push you back with the same amount of force.

These three laws of motion are the basic principles in which the statics and dynamics of bodies are developed.