How safe is your design using 8-mm bolts that yield at 0.5 MPa? That is, can you quantify the extra supplied cross-sectional area as a ratio called the factor of safety?

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.