How fast did the rock strike the ground?

[Makaroon]

Homework Statement

A rock thrown straight up climbs for 2.50 s, then falls to the ground. Neglecting air resistance, with what velocity did the rock strike the ground?

Homework Equations

well we are looking for v=?
we have:
t=2.50 s
and g=9.8
^do we need gravity? yes, right? =S

The Attempt at a Solution

v= d/t
well we only have the time.
so we have to look for the distance... but the distance is ?
do we have to calculate another equation.
ahh please guide me to my answer. :S

thanks.

 

[tiny-tim]

Hi Makaroon!

A rock thrown straight up climbs for 2.50 s, then falls to the ground. Neglecting air resistance, with what velocity did the rock strike the ground?

You have the initial speed (zero), and the time, and you want the final speed.

So which https://www.physicsforums.com/library.php?do=view_item&itemid=204" equation should you use?

 

[Makaroon]

Hi Makaroon!



No you don't!

You have the initial speed (zero), and the time, and you want the final speed.

So which https://www.physicsforums.com/library.php?do=view_item&itemid=204" equation should you use?

hi! would this one be it?
v= u +at
and then resulting to be 24.5.

 

[tiny-tim]

hi! would this one be it?
v= u +at
and then resulting to be 24.5.

Yup!

(moral: write out all the letters you have … in this case u v a and t … and then choose an equation to fit )​

 

[Makaroon]

Yup!

(moral: write out all the letters you have … in this case u v a and t … and then choose an equation to fit )​

That's true.
Thank you so much!
I truly appreciate it! =]