Question

Even though Alice visits the wishing well frequently and always tosses in a coin for good luck, none of her wishes have come true. As a result, she decides to change her strategy and make a more emphatic statement by throwing the coin downward into the well. If the water is 8.23 m below the point of release and she hears the splash 0.93 seconds later, determine the initial speed at which she threw the coin. (Take the speed of sound to be 343 m/s.)

Answer 1

Answer: 4.29 m/s

Explanation:

Given

Depth of the well, s = 8.23 m

Time taken to reach the well, t = 0.93 s

Speed of sound = 343 m/s

To solve this, we would be using one of l the laws of motion.

S = ut + 1/2gt², where

S = depth of the well

u = initial speed of toss

g = acceleration due to gravity

t = time taken to reach the well

We would then have

8.23 = 0.93 u + 1/2 * 9.8 * 0.93²

8.23 = 0.93 u + 4.9 * 0.8649

8.23 = 0.93 u + 4.23801

0.93 u = 8.23 - 4.23801

0.93 u = 3.99199

u = 3.99199 / 0.93

u = 4.29 m/s

Therefore, the initial speed of the coin is 4.29 m/s