# Homework Help: Advance Physics Homework Help

1. Aug 30, 2009

### Leo34005

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

A worker drops a wrench from the top of a tower 111.1 m tall. What is the velocity when the wrench strikes the ground?

m/s downward

2. Relevant equations

x=vt+1/2at^2 intial velocity is 0

3. The attempt at a solution

x = 111.1 + 1/2 ????

2. Aug 30, 2009

### tiny-tim

Leo34005, do you actually understand what these equations mean?

x is distance … that's given, as 111.1 …

(and it's the wrong equation anyway).

Look, in these constant acceleration problems, you can have a u v x and t …

you have to see which of those 5 are given, and which you want (usually 4 out of the 5), and then choose the equation that uses those 4​

3. Aug 30, 2009

### Leo34005

Thanks for helping me get the other problem wrong, now i wont graduate high school

4. Aug 30, 2009

### tiny-tim

You didn't actually do the https://www.physicsforums.com/showthread.php?p=2327280&posted=1#post2327280", so how can you have got it wrong?

you have to see which of those 5 are given, and which you want (usually 4 out of the 5), and then choose the equation that uses those 4​

Last edited by a moderator: Apr 24, 2017
5. Aug 30, 2009

### Leo34005

Can you answer my other problem?

6. Aug 30, 2009

### tiny-tim

Are we talking about the same problem?

7. Aug 30, 2009

### Leo34005

no, the other post

8. Aug 30, 2009

### tiny-tim

ok, but which other post?

9. Aug 30, 2009

### Leo34005

The problem that has this on the post

Two students are on a balcony 23.4 m above the street. One student throws a ball, b1, vertically downward at 15.5 m/s. At the same instant, the other student throws a ball, b2, vertically upward at the same speed. The second ball just misses the balcony on the way down.

(a) What is the difference in time the balls spend in the air?

(b) What is the velocity of each ball as it strikes the ground?
velocity for b1
velocity for b2

(c) How far apart are the balls 0.480 s after they are thrown?