Select the correct answer. samuel adds a teaspoon of salt to a glass of water. he notices that the salt disappears. samuel takes a sip to discover that the water tastes salty. what kind of change has occurred? a. it’s a chemical reaction because a new substance has formed. b. it’s a physical change because the water and the salt kept their original properties. c. it’s an example of synthesis because two substances reacted to give one substance. d. it’s a chemical reaction because the water now tastes salty but originally did not.

Imagine you work as a consultant, and your daily job involves listening to the constructive criticism of others. as part of your job, you must listen to opposing viewpoints to make important decisions. in this activity, you are a consulting dam engineer. you must make a decision about four different dams; should they be repaired, taken down, or left alone? you will listen to contrasting opinions about what should be done with the dams before you make the final decision. as the consulting dam engineer, what do you decide to do with this dam? explain your reasoning. by making your decision, did you support the opinions of the mayor and/or the dam safety official? why or why not? (site 1)

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

Física: un futbolista patea hacia el arco con una velocidad de 15m/ah, calcular: a)el alcance para un ángulo de tiro de 25º, b) el tiempo que el balón permanece en el aire.