# Homework Help: Work Power Engergy Thrown Toilet Roll Problem

1. Jan 9, 2012

### jojo711

1. The problem statement, all variables and given/known data
A pure silver Lions fan throws a roll of toilet paper at 11.0 m/s from her seat at Ford's Field during a recent game. How fast is the 0.4 kg roll going when it strikes an opposition player 17.0 m below?

2. Relevant equations
1/2mv^2 = mgh <-- i think.

3. The attempt at a solution
I did 1/2mv^2 = mgh and got something like 18.25 and then got totally confused and did not know how to do it. Please help. I am totally lost. thanks please answer in the next 20 mintues and you will recieve lots of love. Thanks.

2. Jan 9, 2012

### Delphi51

Yes, definitely an energy question! But I think you have oversimplified a bit. Wouldn't it be
Initial KE + initial PE = final KE

3. Jan 9, 2012

### jojo711

I did:
mgh+1/2mv^2
and got an answer and I don't know what to do from there.

4. Jan 9, 2012

### Delphi51

Initial KE + initial PE = final KE
mgh+1/2mv^2 = 1/2mV^2
Fill in the numbers.

5. Jan 10, 2012

### jetwaterluffy

Which direction are they throwing the roll in?

6. Jan 10, 2012

### Delphi51

We can find the magnitude of the velocity from the final KE. But not the direction because the initial direction isn't given.

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