Friction #1 (Let's Learn Series #22 - Physics)

Hello dear learners, it's been a very long time since my last Let's Learn post. I almost forgot the name of the series 😅

So, in this post, you are gonna learn something we meet and sometimes have troubles and sometimes come in handy. It's Friction!

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So, what is Friction?

According to Wikipedia,

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other

In simple words,

The force that opposes the motion of an object is Friction.

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Let's further clarify this.

If we try to move a table with a low force, it would not move. But it would move with the same force if the table is placed on a smooth surface. All the above results occur because of Friction.

In the first incident, the friction is high so the table doesn't move. But since the friction in the second incident is low, it starts to move. That's why you apply talc or some kinda powder on your carrom board.

Depending on the situations Friction acts on a body, Frictional forces can be divided into three categories as,

The frictional forces that act on an object though the object doesn't move
The frictional forces that act on an object as it just starts to move
The frictional forces that act on a moving object.

Let's do a simple activity to clarify the above three instances.

You'll need,

a block of wood
a newton balance

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Keep the wood on a table or a flat surface and connect the Newton balance to it. Now, apply a little force to the wood so that it does not move. Measure the force using the balance. (instance 1)

Now increase the force and measure the force just when the wood starts to move. (instance 2)

Now measure the force you are applying when the wood is moving. (instance 3)

In the 1st instance, the force is very low. This instance is an instance which shows the frictional forces that act on an object though the object doesn't move. This is known as Static friction.

In the 2nd instance, the force is high compared to both the 1st and 3rd instances. This instance is an instance which shows the frictional forces that act on an object as it just starts to move. This is known as Limiting frictional force.

In the 3rd instance, the force is less than the force in the 2nd instance. This instance is an instance which shows the frictional forces that act on a moving object. This is known as Dynamic friction.