Tuition on Newton Laws of Motion! | Formulas, Examples,..etc

Newton Laws Of Motion

Newton First Law of Motion

Definition- "In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force."

 The property of a body to remain at rest or to remain in motion with constant velocity is called inertia. The inertia of an object is measured by its mass. Mass can be determined by measuring how difficult an object is to accelerate. The more mass an object has, the harder it is to accelerate.

Newton Second Law of Motion

Definition- "In an inertial reference frame, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration of the object: F = ma. (It is assumed here that the mass m is constant )"

Formula

where F is the net force applied, m is the mass of the body, and a is the body's acceleration.

A force is a push or a pull, and the net force $\Sigma F$ is the total force—or sum of the forces—exerted on an object. Adding vectors is a little different from adding regular numbers. When adding vectors, we must take their direction into account. The net force is the vector sum of all the forces exerted on an object.

Newtons Third Law Of Motion

Definition-"When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body."

Formula

Similarly, a car accelerates because the ground pushes forward on the drive wheels in reaction to the drive wheels pushing backward on the ground. You can see evidence of the wheels pushing backward when tires spin on a gravel road and throw rocks backward.

In another example, rockets move forward by expelling gas backward at high velocity. This means the rocket exerts a large backward force on the gas in the rocket combustion chamber, and the gas, therefore, exerts a large reaction force forward on the rocket. This reaction force is called thrust. It is a common misconception that rockets propel themselves by pushing on the ground or on the air behind them. They actually work better in a vacuum, where they can more readily expel the exhaust gases.