Examples Of Newton's Second Law

 Title:- Examples Of Newton's Second Law

Introduction:-

Sir Isaac Newton's Second Law of Motion is a fundamental principle in physics that describes the relationship between the force applied to an object, its mass, and the resulting acceleration. This law, often expressed as F = ma (force equals mass multiplied by acceleration), provides valuable insights into the behavior of objects when subjected to various forces. In this article, I will explore several real-world Examples Of Newton's Second Law in action, highlighting its significance in understanding the dynamics of our physical world.

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Explanation:-

The Basics of Newton's second Law:
Before delving into specific examples, let's establish a clear understanding of Newton's Second Law and its derivation.
Newton's second Law:- Rate of change of momentum of a moving body is directly proportional to its applied external force.i.e
                  F∞ (mv - mu)/t 
=> F= k.m(v-u)/t [ where 'k' is proportionality constant] which is known ,Newton's famous second law of motion
The law is typically expressed as:
F = ma
Where:
F represents the force applied to an object,
m is the mass of the object, and
a is the resulting acceleration.
This equation shows that when a force is applied to an object, it will accelerate in the direction of the force. The acceleration is directly proportional to the force and inversely proportional to the mass of the object. This means that a greater force will lead to a greater acceleration, while a larger mass will result in a smaller acceleration for the same force.

Using Newton's 2nd law of motion ,Prove that  F=ma 

Answer:-

        In the picture, At position A,
  A body  has a mass =m
  It has initial velocity = u
  In this case,

        its momentum = mu
  After applying a force F for a duration of 't' sec the body moves from A to position B
   Now the final velocity of the body is = v
   So, in this case,its momentum is = mv
  ∴ Change in momentum = mv - mu
   So, rate of change of momentum of the body = (mv-mu)/t

 Now,
  according to Newton's 2nd law of motion,
      F∞ (mv-mu)/t
     => F= Km(v-u)/t [where k is a proportionality constant]

=>F = Kma [∵ (v-u)/t =a]
   Now, if F= 1 Newton
          m= 1 kg
         and  a = 1 m/ s²
       then, from (1) we get,
        1=K .1.1
       =>K =1
       Again from (1)
F = 1.ma [ Putting K=1]
=> F = ma   Proved.

    

 Problems related on Second Law Of Motion:-

  Question(1):- A force of 5 N is applied on a moving body of mass 2500 g ,Find the acceleration of the body.
Answer:- Force (F) = 5N
 Mass (m) = 2500g = 2500/1000 kg [ ∵1000g = 1 kg]             = 2.5 kg
       ∴  Acceleration of the body (a) = F/m
                                                    = 5 / 2.5
                                                    = 5.0 / 2.5
                                                    = 2 ms⁻²
 Question (2):- When a force is applied to a moving car of 5ookg gained an acceleration of 1000 cms⁻² ,find the force applied on it.
   Answer:-   Mass of the car(m) = 500 kg
                    Acceleration (a) = 1000/100 ms⁻² [ ∵ 100 cm = 1meter]                   = 10 ms⁻²
       ∴ Force (F) = ma
                           = ( 500 × 10) N

                           = 5000N
Question (3):- After applying a force of 10N on a moving bus,it is accelerated with 2 ms⁻²,Find the mass of the bus.
Answer:-   Force (F) = 10N
             Acceleration(a) = 2 ms⁻²
∴ Mass (m) = F/a
                    = 10/2
                    = 5 kg

Now, I will explore,

Some practical Examples of Newton's Second Law:-

1.Car's Acceleration:-
One of the most common examples of Newton's Second Law is the acceleration of a car. When we press the gas pedal, we apply a force to the vehicle. The car's mass, represented by its weight, remains relatively constant. As we increase the force by pressing the pedal further, the car accelerates accordingly. Conversely, releasing the gas pedal or applying the brakes reduces the force, resulting in retardation or stopping.
This example demonstrates how a change in force can lead to changes in acceleration while the mass remains constant.

2.Falling objects:-

Let,us consider dropping two objects of different mass from the same height, say, a feather and a baseball. According to Newton's Second Law, both objects will experience the same gravitational force due to the Earth's gravity. However, the feather, being much lighter (having less mass) than the baseball, will accelerate more slowly.
This example highlights that, in the absence of other forces like air resistance, all objects fall at the same rate due to gravity. However, differences in mass will still affect how they respond to this force.

3.Rocket propulsion:-

Newton's Second Law plays a crucial role in rocket propulsion. Rockets work by expelling mass in the form of exhaust gases at high speeds. The force generated by this expulsion of mass in one direction (action) results in an equal and opposite force propelling the rocket in the opposite direction (reaction).

The acceleration of the rocket is directly related to the force generated by the expulsion of gas (thrust) and inversely related to the mass of the rocket. As the rocket burns fuel and loses mass, its acceleration increases, demonstrating the law in action.

4.Swinging a base ball bat :-

When a baseball player swings a bat, they apply a force to the bat. The acceleration of the bat is determined by the force applied and its mass. A stronger swing (greater force) will result in the bat moving faster (greater acceleration). Conversely, a heavier bat (greater mass) will require more force to achieve the same acceleration.This example showcases how both force and mass influence the motion of an object, as described by Newton's Second Law.

5.Elevator of acceleration:-

Riding an elevator shows another practical illustration of this law. When an elevator starts moving upward, we feel heavier for a moment. This sensation occurs because the force of acceleration (in this case, upward acceleration) adds to the gravitational force we normally experience. Conversely, when the elevator starts moving downward, we feel lighter briefly.

The change in our apparent weight is a result of the elevator's acceleration (a) and our mass (m) as described by Newton's Second Law. It's a clear example of how force, mass, and acceleration are interconnected.

6.Airbags in car:-
Modern vehicles are equipped with safety features such as airbags  which is based on the principles of Newton's Second Law. In the event of a collision, the airbag rapidly inflates to provide a cushioning effect for the occupants. This is achieved by igniting a small explosive charge, which releases gas into the airbag, creating a forceful but controlled expansion.

The acceleration of the airbag, as it expands toward the passenger, is a result of the force generated by the gas expulsion and the mass of the airbag itself. The goal is to slow down the passenger's forward motion gently, reducing the risk of injury.

7. Rowing a boat:-

Rowing a boat is a nice example where Newton's Second Law comes into play. When a rower pushes the oar through the water with force (F), the boat accelerates in the opposite direction. The mass of the rower and the boat (m) determines the rate of acceleration. A larger force or a smaller mass will result in a faster acceleration of the boat.

Rowing is a practical application of the law in sports and transportation, emphasizing the relationship between force, mass, and acceleration.

8.Weightlifting:-

Weightlifting gives a clear example of how athletes use Newton's Second Law to their advantage. When a weightlifter lifts a heavy barbell off the ground, they exert a force against the Earth's gravity. The acceleration of the barbell is determined by the force applied and the mass of the barbell. The heavier the barbell (greater mass) and the stronger the lifter (greater force), the more challenging it is to accelerate the weight upward.

This example illustrates how athletes manipulate force and mass to achieve their goals, whether in competitive weightlifting or strength training.

9.Space Exploration:-

The exploration of outer space relies heavily on Newton's Second Law. When a spacecraft needs to change its trajectory, it fires thrusters to produce thrust. The force generated by the thrusters, in combination with the spacecraft's mass, determines the resulting acceleration and, consequently, the change in its path.

Space agencies like NASA meticulously calculate and control these forces to ensure spacecraft reach their intended destinations, perform orbital maneuvers, and safely re-enter Earth's atmosphere.

10.Skateboarding:-

Skateboarding shows an everyday example of how Newton's Second Law applies to recreational activities. When a skateboarder pushes off the ground with their foot (applying a force), the skateboard accelerates in the opposite direction. The skateboarder's mass and the force they exert determine the acceleration of the skateboard.

Skateboarders intuitively realise this law as they adjust the force they apply to control their speed and maneuverability on the board.

Conclusion:-

Newton's Second Law of Motion is a fundamental principle that governs the behavior of objects in our physical world. It provides a clear and concise relationship between force, mass, and acceleration, helping us understand how and why things move the way they do.

The Examples Of Newton's Second Law presented in this article span various aspects of our daily lives, from transportation and sports to safety features and space exploration. These real-world applications illustrate the versatility and universality of this law, highlighting its importance in both scientific understanding and practical endeavors. By grasping the principles of Newton's Second Law, we gain valuable insights into the dynamics of motion, enabling us to innovate.........

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Frequently asked questions on EXAMPLES Of NEWTON's SECOND LAW: 

(i).What does Newton's 2nd law state?

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Answer:Newton's 2nd law states that,rate of change of momentum of a moving body is directly proportional to its applied external force.i.e;

F∞ (mv - mu)/t => F= k.m(v-u)/t [ where 'k' is proportionality constant] which is known ,Newton's famous second law of motion.

(ii).What are Newton's 1st 2nd and 3rd laws of motion?

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Answer:If no external force is exerted on a body which is in uniform motion will remain in motion and a body which is at rest remains at rest. This is called Newton's 1st law of motion.

Rate of change of momentum of a moving body is directly proportional to its applied external force.i.e;

F∞ (mv - mu)/t => F= k.m(v-u)/t [ where 'k' is proportionality constant] which is known ,Newton's famous second law of motion.

Every action there is an equal and opposite reaction,and both action and take place simultaneously at the same time.

(iii).What is Newton's 3rd law called?

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AnswerNewton's 3rd law is known as action reaction law.

(iv).What is Newton's third law Class 9?

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Answer:Every action there is an equal and opposite reaction,and both action and take place simultaneously at the same time.

(v).What is Newton's first law name?

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Answer:Newton's first law is also named as law of inertia.

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