7. Explain why observations of comets and shooting stars presented challenges to ancient astronomers using Ptolemy's model to explain the solar system.

Which of the following statements are true of solids? a. the particles do not vibrate. b. the particles are in a fixed location. c. they have strong intermolecular forces between the atoms or molecules. d. the particles have less kinetic energy than those of liquids or gases.

Inside of a windmill or a dam is a that is used to transform one type of energy into electrical energy. a. motor b. generator c. transformer d. power pack

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.