- #1
bobbajobb
- 10
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Homework Statement
Okay, I've been set a piece of coursework to compare the reaction times of catching a ruler, with, or without a certain variable. (I've chosen either eye.)
I'm having trouble working out the exact amount of time it takes the person to catch the ruler. (Yeah, I have attempted it. :) )
Homework Equations
(Explained in section 3.)
The Attempt at a Solution
The ruler weighs 0.025kg.
I hold the ruler at 1.04m. (An average of 10 times holding the ruler at a neutral position)
To calculate the gravitational potential energy I do:
0.025 x 1.04 x 10
This gives me = 0.26 (Joules)
The ruler falls 12 cm, (the person caught it at 18cm)
So 0.025 x 0.12 x 10 = the kinetic energy = 0.03
The formula for speed is :
Speed squared = kinetic energy/(0.5 times the weight)
0.03 divided by 0.0125 = 2.4
The square root of 2.4 = 1.549193338
To two decimal places = 1.55m/s
And if the ruler traveled 12 cm at 1.55m/s
0.12/1.55 = 0.0774 seconds……
I must have gone wrong somewhere...because I swear its 'physically' (pun intended) impossible for them to catch it that quickly?