# Really hard kinematics question

Intr3pid
I was wondering how u solve this kinematics question:

a banana peel is dropped from rest down a shaft. 6.2 s later the sound of the banana hitting the ground is heard. how deep is the shaft

i think:

v1= 0m/s
a=9.8m/s^2

i'm reallu stuck on this one.. don't know where to go from here.

Homework Helper
You also know the time. What you need is a relationship between acceleration, initial velocity, time and distance. Can you think of one?

Intr3pid
Diane_ said:
You also know the time. What you need is a relationship between acceleration, initial velocity, time and distance. Can you think of one?

is this the relationship?

d=v1t+ 1/2 at^2?

Homework Helper
That's the one. Note that one term drops out completely, and you have a relatively easy solution.

Intr3pid
Diane_ said:
That's the one. Note that one term drops out completely, and you have a relatively easy solution.

so I'm guessing v1t drops out since v1 = 0m/s. so i just use plug into d=1/at^2 to solve?

Homework Helper
That would do it.

sweetrose
I'm just wondering if the problem gave you any other information, because you stated this was a really hard kinematics question.

When we were working on kinematics, we worked on a similar problem, but the problem also stated the speed of sound...

If not, then it seems like a relatively easy problem to solve once you write down all the variables and choose the right kinematics equation to use.

Homework Helper
The depth calculated will not that small that the time taken by the sound to come up can be ignored. Particularly when time is 6.2 sec.