A rigid bar used to lift a stone is 100cm long. The pivot is 80cm from the effort. What type of lever is used in lifting the stone. Calculate the load distance. Calculate the mechanical advantage of using this rigid bar.

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.