Question

You want to make a pendulum that has the swing time 1.0 seconds (a so-called "second pendulum"). To help you have a ball and a thin string. How do you go about it? Also account for any values ​​of the mass of the ball, the length of the cord etc.

Answer 1

as the time period of the pendulum is given 1 second and the first expression for Time period of simple pendulum is given by,

T = 2π * √(l/g)

where l is the length of string and g is acceleration due to gravity.

as you can see the time period does not depend upon the mass so you can take any mass of ball which will work like a bob in the pendulum.

now for length we have to solve that expression,

1 = 2π * √(l/9.81)

solving for l,

l = 0.25 m

Thus the length of the string required is 0.25 m or 25 cm.

Final Answer:-

​​​​​​we will tie the ball at one end of the string and allow it to swing back and forth.

Mass of ball =  ball can have any mass as time period does not depend on the mass of bob

Length of string = 0.25 m ~ 25 cm