Newton’s second law is all about understanding the **acceleration** of an object.

That’s it.

Here’s newton’s second law of motion simple definition:

*“The **acceleration** is directly proportional to **net force** applied and inversely proportional to **mass** of an object”*

I know you have not understood the above definition.

Don’t worry, I’ll make it easy for you.

Let’s consider some Everyday Life examples to understand the above statement properly.

## Newton’s Second Law Examples in Everyday Life

Here’s a list of Everyday Life examples of newton’s second law:

- Pushing a car: Small child vs Two boys

- Pulling a horse cart: One horse vs Three horses

- Hitting a ball with the bat: Tennis ball vs Football

- Lifting a courier box: Large vs Small

- Riding a bicycle: Two persons vs One person

- Pushing a trolley: Heavy weight vs Light weight

- And more…

Let’s understand each one of these examples with pictures. (So you’ll get an exact idea)

### #1 Pushing a car: Small child vs Two boys

This is how newton’s second law works, while pushing a car.

When a small child pushes a car… Because of **less force**, a car does not accelerate forward easily.

When two boys together push a car… Because of **more force**, a car accelerates forward easily.

It means that… Acceleration is **directly proportional** to force applied on an object.

(More the force applied on an object, the more it will accelerate)

This thing shows the presence of newton’s second law of motion.

### #2 Pulling a horse cart: One horse vs Three horses

This is how newton’s second law works, while pulling a horse cart.

When one horse pulls a horse cart… Because of **less force**, a horse cart does not accelerate forward easily.

When three horses together pull a horse cart… Because of **more force**, a horse cart accelerates forward easily.

It means that… Acceleration is **directly proportional** to force applied on an object.

(More the force applied on an object, the more it will accelerate)

This thing shows the presence of newton’s second law of motion.

### #3 Hitting a ball with the bat: Tennis ball vs Football

This is how newton’s second law works, while hitting a ball with the bat.

When a man hits a tennis ball… Because of **less mass**, a tennis ball accelerates forward easily.

When a man hits a football… Because of **more mass**, a football does not accelerate forward easily.

It means that… Acceleration is **inversely proportional** to mass of an object.

(More the mass an object has, the less it will accelerate)

This thing shows the presence of newton’s second law of motion.

### #4 Lifting a courier box: Large vs Small

This is how newton’s second law works, while lifting a courier box.

When a courier boy lifts a large box… Because of **more mass**, a box does not accelerate forward easily.

When a courier boy lifts a small box… Because of **less mass**, a box accelerates forward easily.

It means that… Acceleration is **inversely proportional** to mass of an object.

(More the mass an object has, the less it will accelerate)

This thing shows the presence of newton’s second law of motion.

### #5 Riding a bicycle: Two persons vs One person

This is how newton’s second law works, while riding a bicycle.

When two girls are riding a bicycle… Because of **more mass**, a bicycle does not accelerate forward easily.

When one boy is riding a bicycle… Because of **less mass**, a bicycle accelerates forward easily.

It means that… Acceleration is **inversely proportional** to mass of an object.

(More the mass an object has, the less it will accelerate)

This thing shows the presence of newton’s second law of motion.

### #6 Pushing a trolley: Heavy weight vs Light weight

This is how newton’s second law works, while pushing a trolley.

When a boy pushes a heavy weight trolley… Because of **more mass**, a trolley does not accelerate forward easily.

When a boy pushes a light weight trolley… Because of **less mass**, a trolley accelerates forward easily.

It means that… Acceleration is **inversely proportional** to mass of an object.

(More the mass an object has, the less it will accelerate)

This thing shows the presence of newton’s second law of motion.

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There are so many other examples of newton’s second law that we are experiencing in our everyday life.

## Newton’s Second Law Equation/Formula

Here are the three equations of newton’s second law:

**F**_{net}= ma

Where,

F_{net} = net force applied on an object, **N**

m = mass of an object, **m**

a = acceleration of an object, **m/s**^{2}

**p = mv**

Where,

p = momentum of an object, **kg m/s**

m = mass of an object, **m**

v = velocity of an object, **m/s**

**F**_{net}= m(v-u)/t

Where,

F_{net} = net force applied on an object, **N**

m = mass of an object, **m**

(v-u) = rate of change in momentum, **kg m/s**^{2}

mv = final momentum of an object, **kg m/s**

mv = initial momentum of an object, **kg m/s**

v = final velocity of an object, **m/s**

u = initial velocity of an object, **m/s**

t = time, **s**

Let’s solve some problems based on these equations.

### Newton’s Second Law Problems

**Problem 1:** One ball having a mass of 4 kg accelerates forward at the rate of 9 m/s^{2}. Calculate the amount of net force applied on a ball.

**Solution:**

Given data:

Mass of a ball, m = 4 kg

Acceleration of a ball, a = 9 m/s^{2}

Net force applied on a ball, F_{net} = ?

According to newton’s second law equation,

F_{net} = ma

F_{net} = 4 × 9

F_{net} = 36 N

Therefore, the net force applied on a ball is **36 N**.

**Problem 2:** A bicycle accelerates forward at the rate of 4 m/s^{2}, when a force of 10 N is applied on it. Calculate the mass of a bicycle.

**Solution:**

Given data:

Acceleration of a bicycle, a = 4 m/s^{2}

Net force applied on a bicycle, F_{net} = 10 N

Mass of a bicycle, m = ?

According to newton’s second law equation,

F_{net} = ma

10 = m × 4

m = 2.5 kg

Therefore, the mass of a bicycle is **2.5 kg**.

**Problem 3:** Calculate the momentum of a roller which is moving forward with a velocity of 4 m/s. Consider the mass of a roller as 2 kg.

**Solution:**

Given data:

Velocity of a roller, v = 4 m/s

Mass of a roller, m = 2 kg

Momentum of a roller, p = ?

According to newton’s second law equation,

p = mv

p = 2 × 4

p = 8 kg m/s

Therefore, the momentum of a roller is **8 kg m/s**.

**Problem 4:** When a stone having a mass of 5 kg is thrown from a hill, it gains the momentum of 60 kg m/s. With what velocity a stone strikes on the ground?

**Solution:**

Given data:

Mass of a stone, m = 5 kg

Momentum of a stone, p = 60 kg m/s

Velocity of a stone, v = ?

According to newton’s second law equation,

p = mv

60 = 5 × v

v = 12 m/s

Therefore, a stone strikes on the ground with a velocity of **12 m/s**.

**Problem 5:** One truck having a mass of 975 kg is initially at rest. In 20 seconds, a truck attains the velocity of 40 m/s. Calculate the amount of net force acting on a truck.

**Solution:**

Given data:

Mass of a truck, m = 975 kg

Time, t = 20 seconds

Final velocity of a truck, v = 40 m/s

Net force acting on a truck, F_{net} = ?

According to newton’s second law equation,

F_{net} = m (v-u)/t

F_{net} = 975 (40 – 0)/20

F_{net} = 975 × 2

F_{net} = 1950 N

Therefore, a net force of **1950 N** is acting on a truck.

**Problem 6:** A 300 grams skateboard is moving forward with the initial velocity of 110 m/s. When a skateboard strikes with an obstacle, an opposing force of 5 N acts on it. The speed of a skateboard decreases and reaches to 10 m/s. After how much time, a skateboard will come into rest position?

**Solution:**

Given data:

Mass of a skateboard, m = 300 grams = 0.3 kg

Initial velocity of a skateboard, u = 110 m/s

Opposing force acting on a skateboard, F_{net} = – 5 N

Final velocity of a skateboard, v = 10 m/s

Time, t = ?

According to newton’s second law equation,

F_{net} = m (v-u)/t

– 5 = 0.3 (10 – 110)/t

– 5 = 0.3 (- 100)/t

– 5 = – 30/t

5t = 30

t = 6 seconds

Therefore, a skateboard will come into rest position after **6 seconds**.

## Summary

From the above examples, one thing is understood.

**More** the force applied on an object, the **more** it will accelerate.

Similarly,

**More** the mass an object has, the **less** it will accelerate.

That’s how you can easily remember the simple definition of newton’s second law:

*“The **acceleration** is directly proportional to **net force** applied and inversely proportional to **mass** of an object”*

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What do you think, is it easy for you to understand this concept of newton’s second law?

(Let me know in the **comments** below)

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