Newton’s Second Law

In 1687, Sir Issac Newton presented his work on the laws of motion in his book (Mathematical Principles of Natural Philosophy), in which he detailed how objects of various masses move when a force is applied. The first law of motion is related to Newton’s second law of motion. It provides a numerical definition of force. It describes the sources and effects of force and changes in an object’s motion mathematically. Let us look at the three laws of motion before comprehending the equation for Newton’s second law of motion, which deals with an object’s force, mass, and acceleration.

The Three Fundamental Laws of Motion

1. The first law of Newton, also called the law of inertia, is as follows: If a body is in the state of absolute rest, or uniform motion, it will continue to be likewise, provided a foreign force operates upon it.
2. The second law of Newton is as follows: The rate of change of momentum of a body is directly proportional to the external force applied to the body. Furthermore, the body’s momentum is in the direction in which the force is applied.
3. The third law of Newton is as follows: No matter what the activity is, according to this phenomenon, an equal and opposite reaction always abides for it.

“Unless acted on by an outside force, a body abides in its state of rest, or uniform motion,” Newton’s first law states. As a result, the question arises: what happens to your body when you apply an external force to it? The answer to this question is in Newton’s 2nd law of motion.

Based on Newton’s 2nd law of motion, the force acting on a body is equivalent to the rate of change of momentum.

Force is provided by F = ma for a body with a constant mass ‘m’ and the body’s acceleration ‘a’.

According to the preceding equation, if force is doubled, acceleration is also doubled, and if the mass is doubled, acceleration is halved.

Acceleration and Velocity

When a force is applied to an object, Newton’s second law of motion states that the object will accelerate at a rate of change of velocity that is equivalent to the force applied. When force is applied to an item at rest, the object accelerates and moves in the direction of applied force.

The direction of the applied force is important in determining the state of an item that is already moving. When an external force is applied in the object’s direction, the object’s acceleration rises. When an external force is applied in the opposite direction of the object’s motion, the object’s acceleration diminishes and eventually comes to a halt.

Force and acceleration are both magnitude and direction vector values. At the same time, many forces can act on a body.

As a result, ∑F = ma, where =∑ is vector sum of all forces acting on a body (net force).

Application of Newton’s Second Law of Motion

The following are some examples of Newton’s second law of motion in action:

Kicking a Soccer Ball

We add force to a ball when we kick it in a specified direction. This force is in the direction in which the ball is moving. If the applied force is greater, the ball will travel a greater distance, and if the applied force is less, the ball will travel a shorter distance.

Carrying a Cart

Pushing an empty cart is easier than pushing a filled cart because moving an object with a significant mass requires a large amount of force.

Second Law of Motion Examples

When two people of different masses walk together, the person with the heavier mass walks slower than the person with the lesser mass. This is because the lightweight individual produces more acceleration. The following are some examples of Newton’s second law of motion:

• Because a filled cart has greater mass, pushing or pulling an empty cart is easier than pushing or dragging a loaded cart.
• When the same amount of force is applied to drive a car and a bike, the bike will accelerate faster since it has less mass.
• A ball hitting the ground exerts a downward force on the ground and the earth responds by exerting an equal upward force on the ball, causing it to bounce.
• It takes a lot of force to stop a moving ball.

Conclusion

The second law of Newton states that the rate of change of momentum of a body is directly proportional to the external force applied to the body. Furthermore, the body’s momentum is in the direction in which the force is applied. Two variables, namely, the net force acting on the object and the mass of the object, determine an object’s acceleration. The acceleration of a body is proportional to the net force exerted on it and inversely proportional to body’s mass. This means that as the force acting on an object increases, so does the object’s acceleration. Similarly, as an object’s mass grows larger, its acceleration decreases.