A 15 kg box of books is moved from a height of 8 meters to a height of 3.5 meters. What is the work done on the box of books?

What will a positive and a negative charge do if they are separated from each other?

What is the measurement of how fast an object moves relative to a reference 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.