Have you heard an ambulance, police car, or fire truck recently? did you notice that the pitch of the siren changed as it approached you and then again as it moved away? what concept explains this change or shift in sound waves?

Lets say that an object of a certain volume has a certin mass. what happens to its mass when you double its volume?

Apackage of supplies is dropped from a plane, and one second later a second package is dropped. neglecting air resistance, the relative velocity of the 1st package viewed from the second will 56) a) increase. b) be constant. c) be zero. d) depend upon their weight. e) decrease

Which configuration would produce an electric current? a) rotate a coil of copper wire between two magnets. b) connect a wire between a copper and zinc strip sitting in a beaker of water. c) connect a wire to the (+) positive end of a battery and the other end to a light bulb. d) connect a wire to the negative end of a battery and the other end to a light bulb.