Parts of a device that use radio waves. On the left is a box labeled A. On the right is a box labeled B. There is a vector pointing up from Box A and a vector pointing down to Box B. Arrows pointing left from Box A to Box B are labeled Radio waves travel through the air. Which part, A or B, captures, amplifies, and demodulates radio waves? Which part , A or B, modulates, amplifies, and sends out radio waves?

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒

Ms. hidalgo opens the door to her classroom. her classroom is 60 degrees and the air outside is 80. predict what will happen using your knowledge of how heat flows.