- #1

_physics_noob_

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## Homework Statement

A meter stick is held vertically above your hand, with the lower end between your thumb and first finger. On seeing the meter stick released, you grab it with these two fingers. You can calculate your reaction time from the distance the meter stick falls, read directly from the point where your fingers grabbed it.

**If the measured distance is 17.6cm , what is the reaction time?**

So I googled it and it said t=√d/4.9m/s^2

How is that derived?

## Homework Equations

v2=v1+at

x=v1t+1/2at^2

x=1/2(v1+v2)t

v2^2=v1^2+2ax

## The Attempt at a Solution

I converted 17.6cm to 0.0176m. Now my question is how would I approach this kind of question without all the given variables?

This is my attempt at it.

x=0.176m

a=-9.8m/s^2

0.176=v1t+1/2(-9.8m/s^2)t^2

0=-0.176+v1t+(-4.9m/s^2)t^2

but now I don't have a variable for v1 how to solve for v1

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