Question

Problem 1: Reaction Time Figure below shows a simple technique for measuring your reaction time. A friend holds a meter stick vertically, with thumb and forefinger at one end as shown. You then position your thumb and forefinger at the other end, being careful not to touch the meter stick. Your friend releases the stick, and you try to pinch it as soon as possible after you see it begin to fall. After multiple trials you find that the meter stick has fallen an average distance of 30 cm through catcher's (your) fingers. (a) Use equation(s) of one dimensional kinematics to determine your reaction time. (b) Alcohol can slow your reaction time by as much as 30 %. Drugs can slow your reaction time by as much as 50 %. Tests show talking on a cell-phone while driving can slow your reaction time by as much as 20 %. Calculate your reaction times on alcohol, drugs, and on a cell phone. Do these results surprise you? How might these slowed reaction times affect your performance of daily activities?

Answer 1

a) The reaction time can be calculated as ,

$S= \frac{1}{2}gt^2$

$0.30= \frac{1}{2}\times 9.8\times t^2$

b) By alcohol, the reaction time can be slows down to,

$t = 0.78+0.78\times \frac{30}{100} = 1.014 sec$

By drugs, the reaction time slows down to,

$t = 0.78+0.78\times \frac{50}{100} = 1.17 sec$

By talking on cell phone, reaction time slows down to,

$t = 0.78+0.78\times \frac{20}{100} = 0.936 sec$