Running+Straight

So we realized that for the hammer to be in circular motion, the pull from the chain towards the center must be applied

Now let’s, investigate runners taking a bend.

Before asking what they are doing at a bend let us try to understand what they are doing while running straight.

Look at the feet of a runner when he is running straight.



It is possible to recognize that the feet when they are in contact with the earth push hard on earth in the backward direction.

Then how you move forward?

Let’s bring in a small piece of physics in here J to understand the action going on here.

Action Reaction Pair

I am sure we all remember hearing somewhere, “for every force there is an equal and opposite force”.

This is the 3rd Law of Newton.

According to this Law, all forces arise as pairs. But each force in the pair act on a separate object

Think about any instant you pushed something.


 * You push the wall, the wall pushes you back.
 * Your push acts on the wall and the wall’s push act on you. (two forces on two objects)

You pull the hand of a friend to help him to climb a hill; you will feel his hand pulling you down



The pull by you act on the friends hand and the pull by the friend acts on your hand.

The same thing that happens when you are running or walking

You push the earth backward, and the earth pushes you forward. The push from the earth is what makes you move forward



So now we know each force we apply on something is generating a reaction force on us.

Now, we can look at moving in circles examples with this idea.