Assuming you are on earth, where acceleration due to gravity is 9.81 meters/second2, and you have a pendulum with a cord that is 0.65 meters long, what is the period?

Here, Time of Period(T) = 2π√l/g
Here, l = 0.65 m
g = 9.81 m/s²

Substitute their values, 
T = 2π×√(0.65/9.81)
T = 6.28 × 0.066
T = 1.616
T = 1.62 s  [ After round-off to the nearest hundredth ]
 
In short, Your Answer would be 1.62 seconds

Hope this helps!

Sorry i don’t know what to do