Please help me solve the following problem. A stone is thrown vertically downward from a cliff 202.0m tall. During the last half second of its flight, the stone travels a distance of 46.1 m. Find the initial speed of the stone.

Question

Please help me solve the following problem.  A stone is thrown vertically downward from a cliff 202.0m tall. During the last half second of its flight, the stone travels a distance of 46.1 m. Find the initial speed of the stone.

anonymous · Answer

Well.. consider total time as t.. then you can divide the sum into two parts

fall during first t-1 seconds.. and fall during next 1 second

since you know what is the height of cliff.. and what is the distance travelled in last second.. you can find out what is the distance travelled in first t-1 seconds.. now use equation of motion and get an equation in t and u

now using this data.. use the equation of motion for the second part.. the last second