A lens produces a real image by causing light rays from a common point to 1.) coverage and intersect at a point 2.) disperse into component wavelengths 3.) reflect constructively 4.) diverge and appear to come from a point

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.