# Homework Help: Impact Speed (?)

1. Aug 30, 2006

### Kalie

Ball bearings are made by letting spherical drops of molten metal fall inside a tall tower called a shot tower and solidify as they fall.
If a bearing needs 4.50 to solidify enough for impact, how high must the tower be?
What is the bearing's impact speed?

I got the answer for the first part correct it was 99.2
d=.5*9.8*4.5^2=99.2
but I am not sure how to approach the second part.....

What is the bearing's impact speed?
I search all over but couldn't find an equation could someone help me with that.
All I need is the equation.....thank you

2. Aug 30, 2006

### mezarashi

Look for the kinematics equations. Given all the information you have, you actually have a choice on the equation you want to use.

How about the intuitive: final velocity = initial velocity + (acceleration x time)

3. Aug 31, 2006

### HallsofIvy

You know that v= -9.8 t m/s2 and t= 4.5 s!

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