Erin's reaction time

You guys in the after lunch bunch, Sec. 0002, we forgot to calculate Erin's average reaction time! Oh, no!

Here are the drop distances:

1. 30 cm
2. 20 cm
3. 21 cm
4. 8 cm

And the average drop distance is (79 cm)/4 which is 19.75 cm.

Now: we know what the general formula for drop distance is, connecting drop distance with drop time, second by second.


So for Erin, her average drop distance equals one half g times the square of her reaction time:


Better convert those centimeters to meters.


Now: divide both sides by 4.9, and you get t_reac² = 0.0403 sec². Hit the square root key on your calculator, and you get Erin's reaction time, t_reac = 0.20076 sec, very similar to Kendall's reaction time from the morning section 0001.

Nice work, Erin and Kendall.