(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I am in highschool 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.

2. Relevant 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?!!?

3. The attempt at a solution

Now, the problem calls fortime, 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

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# Homework Help: At which times will the ball be at a height of 15 meters?

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