Can You Calculate the Rock's Speed Without Considering Sound Delay?

[katyross]

Homework Statement

"A rock thrown horizontally at a large bell 50m away is heard to hit the bell 4.5 seconds later. If the speed of sound is 330m/s, what was the speed of the rock? (Disregard the effect of gravity.) [Hint: If it requires a time of t for the sound to return, then it requires (4.5 s-t) for the stone to reach the bell]

Homework Equations

v = d/t

The Attempt at a Solution

Would you completely disregard the speed of sound, and continue using the v= d/t?

v = 50 / 4.5
v = 11.1 m/s

 

[cristo]

No, I would use the speed of sound, and the hint.

 

[katyross]

how would you fit that into the formula to find the speed of the rock?

 

[cristo]

how would you fit that into the formula to find the speed of the rock?

It tells you that if t is the time the sound takes to travel from the bell to your ear, then (4.5-t) is the amount of time the stone takes to travel to the bell.

How can you calculate t, given the speed of sound and the distance travelled?

 

[katyross]

v = d/t

t= d/v
(4.5-t) = 50/330

?