A simple pendulum executes 40 complete oscillations in a minute. What is the effective length of the pendulum? `g=980cm*s^(-2)`.

Explanation

Time period (T) = `60/40=3/2s`
Now, `T=2pisqrt(L/g)or,T^(2)=4pi^(2)L/g`
or, `L=(gT^(2))/(4pi^(2))=(980xx(3/2)^(2))/(4xxpi^(2))=55.9`cm.