The Burj Khalifa is the tallest building in the world with a height of 0.828 km. On his delivery on Christmas Eve, Santa Claus accidentally bumps into the Burj Khalifa and drops a toy from the very top of the building. What is the magnitude of the velocity (in m/s) of the toy 0.642 km from above the ground? Neglect air resistance. g=9.81m/s2

An object with initial temperature 130 ∘ f is submerged in large tank of water whose temperature is 50 ∘ f . find a formula for f ( t ) , the temperature of the object after t minutes, if the cooling constant is k = − 0.2 . remember newton's law of cooling (the rate of change of temperature with respect to time is equal to k times the difference between the temperature of the object and the surrounding temperature) ! : )