After a lockdown drill at a school, the management team noted that the lockdown siren has a low volume and low pitch making it difficult to be heard at a distance. They called the company that supplied the siren and asked them to make the alarm louder and to give it a higher pitch. What effect does the change have on the resulting sound wave produced by the siren

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s