# Homework Help: Melting a snowball by throwing it at a wall

1. Feb 7, 2013

### AbsoluteZer0

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

You throw a snowball at 0.0 Celsius at a brick wall. If you want it to melt completely, how fast will you have to throw it?

2. Relevant equations

$Q = mL$

$E_k = \frac{1}{2} mv^2$

3. The attempt at a solution

I initially reasoned that you would use Q = mL to find the energy needed to melt it and then substitute that into the Kinetic energy formula, giving:

$mL = \frac{1}{2} mv^2$

However, I am given no information regarding the mass of the snowball and haven't figured out a method to find that mass.
Any suggestions?

Thanks,

2. Feb 7, 2013

### Saitama

Why do you need mass when it cancels out in the equation you formed?

3. Feb 7, 2013

### trollcast

Just assume that mass equals 1.

4. Feb 7, 2013

### AbsoluteZer0

Ah!
I didn't notice that. Thanks.

I'm now at

$L = \frac{1}{2}v^2$

Edit:

I changed 334 j/g to 334000 j/kg and arrived at around 800 m/s

Last edited: Feb 7, 2013
5. Feb 7, 2013

### haruspex

If you want your working checked, please post it.