Starting with the second law of motion, while the first one discussed the relationship of forces acting upon an object, the second is about unopposed or unbalanced forces.
As stated earlier, the second law provides for a wider range of applications. This article discusses Newton’s second law with various examples in great detail.
What Is Newton’s Second Law Of Motion?
Newton defined it in the following way: For a variable mass, force is equal to the rate of change of the body’s momentum. For a constant mass, force equals mass times acceleration.
Isaac Newton, in his words: In other words, Newton’s second law prescribes how much the motion of a body will be changed as a result of the acting force.
Mathematically, it states that the time rate of change of a body’s momentum is equal to the force exerted on the body in the same direction as the force vector imposed on the body. The momentum of a body can be defined as the product of an object’s mass and velocity.
As with velocity, momentum is also a vector quantity, so it will have a direction and value as well. The application of force on an object will either change its yielding and thrust motion or its directional movement, or both forces will be exerted onto it.
In the entire spectrum of physics, the two laws of Newton are given utmost importance. The second law states that: For a body, having a constant mass m, it can be expressed as F = ma, where F (force) and a (acceleration) are both vectors.
If a body possesses a net force on it, it is accelerated in accordance with the equation. In case a body does not accelerate, it is understood that there is no net force acting on it.
Examples Of Newton’s Second Law Of Motion In Everyday Life
The example of pushing a person to identify the force that is needed to move a resting human body and to cease motion illustrates an application of the second law of Newton. We will look at signs do apply, such as follows:
1. Kicking A Ball
When we perform the action of kicking a ball, we apply force in a definite direction. The greater we kick the ball, the larger the distance the ball will travel.
2. Pushing A Cart
The effort required to push a shopping cart is less as compared to working on a filled cart. The direct relationship between time and a cart being pushed demonstrates that an increase in mass requires less needs more propulsion to move.
3. Two People Walking
These two people walking will show the difference in weight as one of them will walk slower. A heavier person walks slower while a lighter person accelerates more.
4. Pushing A Car And A Truck
Newton’s second law of motion can be experienced in real life when trying to move a car and a truck with the same force.
It is easy to notice that after pushing a car and a truck with the same intensity, a car accelerates far more than a truck. This occurs because a car has a lower mass than a truck.
5. Hitting A Ball
When hitting the ball, we see that the ball starts gaining acceleration. The amount of force applied will change the rate of acceleration when moving the ball.
In other words, for example, hitting the ball harder will definitely make it move faster, which is an example of Newton’s second law of motion formed in real-life situations.
6. Rocket Launch
Rocket Launch In order for a rocket spacecraft to leave Earth’s orbit and travel into outer space, a force known as thrust is required. According to Newton’s second law of motion, “force is proportional to the acceleration.”
Thus, for a rocket launch, the magnitude of thrust is increased to increase acceleration. In turn, the speed achieved by the rocket surpasses Earth’s gravitational field and transitions into space.
7. Car Crash
Car Crash Essentially, there exists a force between a barrier and the car during a car crash which is referred to as impact force. Impact force magnitude is determined by the mass of the colliding objects and the velocity at which the objects are moving.
In this case, the greater the mass of the objects involved in the collision, the greater the intensity of the impact force will be. In the same manner, the magnitude of impact force is directly proportional to the acceleration the car possesses.
8. Object Thrown From A Height
When an object is thrown from a certain height, the acceleration is induced by the pull of gravity towards the earth.
While falling, an object perpetually gains acceleration, which is according to Newton’s second law of motion, states that acceleration developed by a body is directly proportional to the force acting on that body.
The acceleration continues to build, and tremendous impact force is generated as the object strikes the surface below.
This explains the phenomenon where brittle objects experience extreme deformity when dropped from very tall structures compared to less rigid structures.
9. Karate Player Breaking a Slab Of Bricks
A karate player elegantly executes the second law of motion while completing the task of breaking a slab of bricks.
Knowing very well that force is proportional to acceleration, the player moves his arms, palms facing upward, and begins to sweep them across the upper surface of the slab very rapidly.
This action enables him to gain considerable acceleration which in turn generates a significant amount of force. That amount of force inflicts the slab with too much stress and breaks it into two or more bricks.
10. Driving A Car
To put it into simpler words, Newton’s second law of motion says that if any part of a system that has mass is acted upon by a force, that force will result in acceleration of the system as well.
As an example, when we switch on the ignition system of the automobile, the automobile’s engine provides sufficient force that allows the car to move with equal and proportionate acceleration.
11. Racing Car
When trying to speed up racing cars, engineers seek to make the cars lighter to increase speed. This is true because lower mass results in greater acceleration and faster speed, which means winning the race is more likely.
Real-Life Examples Of Newton’s Second Law
Here are 50 examples that illustrate real-world scenarios of the application of Newton’s second law:
- Putting force on an automobile to make it gain speed.
- Kicking a soccer ball to set it into motion.
- Dragging a sled with constant effort.
- Steering a boat forward through the water.
- Striking a baseball using a baseball bat.
- Tossing a basketball towards the net.
- Gaining speed on a bicycle through pedaling.
- Raising a backpack while opposing the gravitational pull.
- Pushing a suitcase across a flat surface.
- Propelling a shopping cart in a market.
- Here are some different ways to phrase the same activities:
- Moving a pendulum to and fro.
- Shooting a rocket off into the atmosphere.
- Skateboarding on an inclined platform.
- Gliding elegantly on ice rinks.
- Setting off a small rocket.
- Throwing a frisbee for a friend to catch.
- Rolling a ball into a bowling alley track.
- Striking a golf ball using a golf club.
- Going down a slide in the playground.
- Sitting on one side of a seesaw.
- Doing a handstand with the butt sticking up.
- Standing on a handboard, springing into a pool.
- Maneuvering a car that moves via remote control.
- Squeezing a ball made of rubber.
- Riding on a swing while it’s going.
- Pushing open a door that weighs a lot.
- Facing backwards on a rollercoaster.
- Writing with a Sharpie.
- Getting the tires of a car on a punk.
- Skating on roller skates.
- Holding hands with an infant while they sit in a stroller.
- Taking a slice of an air-filled puck and putting it on the table.
- Putting shoes on top of a body that rests on the edge of a bed.
- Running two caps filled with oil.
- Rotating a pancake while it cooks in a frying pan.
- Guiding a snowball as it descends a slope.
- Bringing a sledgehammer downwards with force.
- Moving a hula hoop around one’s midsection.
- Descending a slope on a snowboard.
- Activating a fire extinguisher to quench flames.
- Hand cranking a device to draw water from a well.