- #1

Gdsykes

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## Homework Statement

I am in high school physics. This is my problem that I've been trying to work on:

*A ball is thrown straight upward with a velocity of +20m/sec on a planet where the acceleration due to gravity is -10m/sec². Find the times at which the ball will be at a height of 15 meters.*

## Homework Equations

Ok, so I started with this equation:

**D=ViT+½at².**I'm not sure if it's the correct one to use, but I'm pretty sure it is...I think I will need to use the quadratic forumla: x= -b+-b²-4ac (square root)/2a. Sorry, I don't know how to make a square root symbol or any of the other signs?!?

## The Attempt at a Solution

Now, the problem calls for

*time*, so I must need to solve for it. Next, I got this as the possible equation to utilize when it's solved for time: t-v+- v²+f(1/2a)d (square root) / 2(1/2a)

So far, does everything seem to be right, now all I need to do is "plug and chug?" :) Thanks

-Greg