# Homework Help: Given height find how fast its moving

1. Oct 5, 2008

### kmiller

given height find how fast its moving....

1. The problem statement, all variables and given/known data

Seagulls are often observed dropping clams and other shellfish from a height to the rocks below, as a means of opening the shells. If a seagull drops a shell from rest at a height of 6 m, how fast is the shell moving when it hits the rocks?
find m/s

3. The attempt at a solution

6m/9.8=58.8 wrong
i cant figure it out help please

2. Oct 5, 2008

### Mattowander

Re: given height find how fast its moving....

What equation did you attempt to use?

Are you not aware of the kinematics equations?

3. Oct 5, 2008

### kmiller

Re: given height find how fast its moving....

I am using motion eqautions, Vf=Vi+at

4. Oct 5, 2008

### Mattowander

Re: given height find how fast its moving....

But you're not given the time. You're only given the initial velocity, the distance, and you know the acceleration due to gravity. That is not the correct formula to use. What other formulas are there for kinematics?

5. Oct 5, 2008

### kmiller

Re: given height find how fast its moving....

VF2=Vi2+2a+(delta)

or

Xf=Xi=Vit=.5at2

6. Oct 5, 2008

### Mattowander

Re: given height find how fast its moving....

The first equation is correct.