How & When are the forces created
As you can see we have discussed the direction of applied forces change direction at every point in a circular moment.
Basically if we try to understand the forces, The Force will always remain perpendicular to the string.
As shown in figure 1,2,3 & 4
Every time when a perpendicular force was applied to the ball, It tried to move in the direction of the force. But as the ball was attached to the string the force changed its direction.
See figure
:
In figure 1 we see force F1 is applied in one direction.
Now in Figure 2 we can see at a point force r2 is also applied to it, The point is marked as a collision point of forces. Thus a new force is generated which is in a different direction.
As per the law & Defination in a circular motion the force applied is perpendicular to the string which one end is attached to the object and other end is attached to the string .
So now we study different cases.
If in Case 1
As we see in figure 1 & 2 we can see the force is applied to the ball and the ball changes its position.
But in this case r=4.5 cm & r1=5 cm
But in a circular motion r=r1
So now we look on to case 2
In this case the object changed its position but r=r1
You can see that the object did not move in the perpendicular direction.
Thus if for a circular motion case 2 is a perfect match.
Therefore during a circular motion at each point where the string will be short a pull force will be applied and a new force will be introduced (Fn)
And all the force will be applied to the object in their respective directions till they become zero.
Creating Relationships 