Question

Phy 1010 – Chapter 2 Activity: Measure your reaction time.

Requires a ruler and a friend to help you.

Hold the index finger and thumb of your dominant hand about 2.5 cm apart, and have a friend hold a ruler vertically in the space between your fingers and thumb.

Note the position of the ruler relative to your index finger.

Your friend must release the ruler, and you must catch it (without moving your hand downward) as quickly as you can.

The ruler is in free fall. It falls a distance d = ½ g t², where tis the reaction time and

g= 9.80 m/s².

Repeat the measurement of d five times, average your results, and calculate the average value of t.

                        

d1	d2	d3	d4	d5
6.5	5	8.5	4	5.5

d_average= (6.5+5+8.5+4+5.5)/5=5.9m

t=

Now measure your friend’s reaction time and compare. For most people the best reaction time is about 0.2 s.

d1	d2	d3	d4	d5
4.5	8	5.3	4	4.75

d_average= (4.5+8+5.3+4+4.75)= 5.31m

t=

Answer 1