Aroller coaster has a mass of 250 kg. it drops from rest at the top of a hill that's 88 m tall. how fast is it going when it reaches the bottom? acceleration due to gravity is g = 9.8 m/s2.
a.41.5 m/s b.13.1 m/s c.52.2 m/s d.70.0 m/s

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.