Why was Henry Cavendish's experiment to determine the value of G called the "weighing-the-earth experiment"?

A2-kg bowling ball is 2.5 meters off the ground on a post when it falls. just before it reaches the ground, it is traveling 7 m/s. assuming that there is no air resistance, which statement is true?

Acircuit contain a 5-ohm,a3-ohm,and an 8-ohm resistor in series. what is the total resistance of the circuit

Patients with brain tumors may elect to have a procedure known as gamma knife. in a typical gamma knife procedure gamma rays are directed toward a tumor with contact to surrounding tissues. limiting contact between gamma rays and healthy tissue is important because