What happens to a light wave that travels through glass and strikes a boundary with water at a 45° angle?
A. It refracts in the water, toward the boundary.
B. It reflects back into the glass in the direction it was traveling from
C. It reflects back into the glass with a 45° angle of reflection.
D. It refracts in the water, away from the boundary.

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.