Have you ever thought of how everyday phenomena happen, such as small balls rolling faster than large balls? Why do you fall in the forward direction when a car stops suddenly? Or why does a rolling ball stop when it hits a wall? The answer to all these questions is hidden in Newton’s three laws of motion. You can find out more about these laws of motion with daily life examples in this article.
Newton’s First Law of Motion
Imagine you are going to an amusement park with your friends. You are all sitting in the car, but to go to the park, the driver will need to start the car. The car will not start on its own unless it is a magical car!
This is Newton’s First Law of Motion. Any object will stay at rest or in uniform motion unless an outside force (here, starting the car or applying brakes) is acting on it.
The outside force that is applied does not have to come from humans, but can be from a combination of sources. For example, if you throw a ball, it will eventually slow down and fall to the ground due to the atmosphere’s friction and to gravity.
The ability of an object to remain at rest or in motion is known as inertia in physics. Our world would be a completely mad place to live in if it were not for inertia. Imagine studying in your classroom with occasionally moving desks and chairs, landing in a neighbor’s garden while eating meals at the table, or never being able to reach home because the school bus would not stop.
First Law of Motion Examples
Example 1: When a car stops suddenly, the passengers still feel forward motion. This is due to the inertia of motion whereby the car begins to stop while the body inside is still in a state of motion.
Example 2: When you turn off a table fan, the blades continue to move for some time even without electricity because of the First Law of Motion.
Example 3: A dirty dish lying on the table will not move or get cleaned unless you apply some force and put it in the dishwasher.
Newton's Second Law of Motion
As we know, to move an object some force is required. But how will we know how fast it will move? This is acceleration, and Newton found that it depends upon two things: the mass of the object and the force used on it.
Now, imagine you are in a supermarket with your friend. Your cart has 5 apples while your friend’s cart has 50 apples. The masses of both carts are different; your cart is lighter than your friend’s cart. So, when the same force is applied, they will travel at different speeds and cover different distances. If you increase the force of pushing, the lighter cart will move farther away.
This is Newton’s Second Law of Motion. An object speeds up (here the cart) due to the force acting on it. In short, acceleration of an object is linked to the force which is acting on it.
Expression of Second Law of Motion
You can calculate acceleration by using this formula: a = F ÷ m.
Here, a = acceleration
F = force used
m = mass of the object
So, you can conclude from the formula that:
The greater the force applied to an object, the greater will be the acceleration.
The greater the mass of an object, the greater the force needed to move the object.
Second Law of Motion Examples
Example 1: When we kick a soccer ball in a specific direction, we are exerting force on the ball. The harder we kick, the more force we apply, and the farther the ball goes.
Example 2: In racing cars, engineers try to keep vehicle mass as low as possible. This means with lower mass more acceleration can be provided. If the acceleration is higher, the chances of winning the race are also increased.
Example 3: During a car accident, the force between the car and the obstacle is known as impact force. This force depends on the masses of colliding vehicles and the speed at which they are moving. This means that if a bigger and heavier vehicle moving with greater speed is involved in a collision, the intensity of the impact force will be greater.
Newton's Third Law of Motion
Now, try jumping on the ground. Your feet are applying force on the ground, and the Earth is applying an equal and opposite reaction force that pushes you into the air. You may not feel it initially, but if you jump harder, you will feel a little pain in your feet. This pain is the result of the equal and opposite force applied by the Earth.
This is Newton’s Third Law of Motion, stating that forces always occur in pairs. To every action (here you jumping), there is an equal and opposite reaction (the Earth pushing back).
Third Law of Motion Examples
Example 1: When you sit in a chair, you are constantly pushing on the chair with a downward force. The chair is also pushing you back with an upward force; otherwise, the chair would collapse and you would fall.
Example 2: Birds also fly using the Third Law of Motion. The wings of the bird push the air, creating an upward force which helps them move forward. Airplanes and helicopters also use this technique.
Example 3: While swimming or moving in a rowboat, when you push the water backward, there is an equal and opposite force generated which causes forward motion.