How to find the velocity needed to melt a snowball

[TextClick]

Homework Statement

With what velocity must a snowball at 0 C be thrown so that it completely melts upon striking a stone wall? (Assume 75% of the heat generated is absorbed by the snow.)

Relevant Equations

Q=mCdeltat
Q=mHv
Q=mHf
KE=1/2mv^2
PE=mgh

I attempted a solution, but I was unfortunately confused and did not know how to do the problem. As a result, I did not do any work.

 

[haruspex]

Homework Statement:: With what velocity must a snowball at 0 C be thrown so that it completely melts upon striking a stone wall? (Assume 75% of the heat generated is absorbed by the snow.)
Homework Equations:: Q=mCdeltat
Q=mHv
Q=mHf
KE=1/2mv^2
PE=mgh

I attempted a solution, but I was unfortunately confused and did not know how to do the problem. As a result, I did not do any work.

Nevertheless, you need to post an attempt, no matter how confused. That way we may be able to see where you are confused and help you become unconfused.

 

[TextClick]

 

[haruspex]

You arrived at an answer, but it is impossible to tell from those few scribbles how you arrived at the required energy. Please post the details of your working , and not as an image. Per forum rules , images are for textbook extracts and diagrams.

 

[DEvens]

Pretty sure you are meant to determine the amount of heat required to melt a unit of snow. That's what the Hf is for. Then you are supposed to find out how fast it must be moving so that 3/4 of it's Ek equals that much.

So you should do the problem with a variable mass, since you don't know what the mass of a snowball is. But the mass should divided out at the end.

It looks like the person who marked this quiz wrote the correct answer for you. They even wrote the equations.

Can you make an attempt?