Answer:
Time period for Simple pendulum, 
Explanation:
The Simple Pendulum
Consider a small bob of mass  is tied to extensible string of length
 is tied to extensible string of length  that is fixed to rigid support. The bob is oscillating in the plane about verticle.
 that is fixed to rigid support. The bob is oscillating in the plane about verticle.
        Let  is the angle made by string with vertical  during oscillation.
 is the angle made by string with vertical  during oscillation. 
Vertical component of the force on bob,  
 
Negative sign shows that its opposing the motion of bob.
Taking  as very small angle then,
 as very small angle then, 
 
    
Let  is the displacement made by bob from its mean position ,
 is the displacement made by bob from its mean position ,
then, 
so,  ........(1)
                ........(1)
Since, pendulum is in hormonic motion,
as we know, 
where  is the constant and
 is the constant and 
 .........(2)
                   .........(2)
From equation (1) and (2)


Since, 

