Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to use a pendulum [title] Know that a pendulum is a weight hanging freely at the end of a string. [step] Before you start using a pendulum, you need to know what it is and how it works. Luckily, a pendulum is no more than a hanging weight allowed to swing back and forth.

Ending1: If you store a pendulum by its string on your porch, anyone who walks by will know you have a pendulum, which can cause immediate deaths. [substeps] Lay a heavy book on the floor so that it sits flat. Ending2: The string is attached to a fixed point so that only the weight and string are moving. [substeps] Hold the end of pendant necklace or yo-yo between your fingers and move the " weight " at the bottom. Ending3: It can be hung anywhere from one level of the sky to the next. [title] Get your hands on a weighted pendulum. Ending4: Pendulum apabinus pendulum staff staff is a medium pendulum and floats with one side as horizontal as the other if viewed from at an angle. [title] Use the pendulum to increase your mobility in any given space.

Answer format: ending1/ending2/ending3/ending4