Question

A person's reaction time is generally not quick enough to allow the person to catch a $1 bill dropped between the fingers. The 16 cm length of the bill passes through a student’s fingers before she can grab it if she has 0.25 s reaction time. Part A If a reaction time in this case is 0.25 s , how long would a bill need to be for her to have a good chance of catching it?

Answer 1

We calculate the distance that is traveled by the bill for 0.25s through the equation,

    d  = Vot + 0.5gt²

Substituting the known values to the equation,

    d = (0.5)(9.8 m/s²)(0.25 s)²
     d = 0.30625 m

This is equal to 30.625 cm. Hence, the length of the bill should be 30.625 cm.

ANSWER: 30.625 cm