# Homework Help: Free Falling bodies

1. Sep 21, 2009

### pookisantoki

1. The problem statement, all variables and given/known data
A wrecking ball is hanging at rest from a crane when suddenly the cable breaks. The time it takes for the ball to fall halfway to the ground is 1.31sex. Find the time it takes for the ball to fall from rest all the way to the ground.

I think the formula to use is t=vfinal-vinitial / g
But not sure what vfinal is to use this formula so I am stuck...

2. Sep 21, 2009

### semc

Hey dude try using this formula: X=X+vt+0.5at^2

3. Sep 21, 2009

### pookisantoki

with that formula
a=-9.8
t=1.31sec
where would the X come from??

4. Sep 21, 2009

### semc

Xfinal=Xinitial + vt + 0.5at^2. i believe you know Xinitial?

5. Sep 21, 2009

### pookisantoki

I believe the x initial is 0 and xfinal is .5 since it's half way but not sure how I would find "v" from the question so that I can find "t"

6. Sep 21, 2009

### semc

the v is vinitial so what should the initial velocity of something that is at rest be?