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The following simple method can be employed to determine reaction time. A partne

ID: 2174903 • Letter: T

Question

The following simple method can be employed to determine reaction time. A partner holds a meterstick by pinching it at the top and letting it hang vertically. To measure your reaction time, place your thumb and forefinger just below the base of the meterstick, ready to pinch it when it falls. Without signaling, your partner releases the meterstick; it accelerates due to gravity at a rate of 9.8 m/s2, and you grab it as fast as possible.

t = 0.14 s d = cm t = 0.16 s d = cm t = 0.18 s d = cm t = 0.20 s d = cm t = 0.22 s d = cm

Explanation / Answer

(a) y = (vo)(t) + 0.5at^2 where y is the vertical displacement of the meter stick (y = -0.4 m) where vo is the initial vertical velocity (vo = 0 m/s) where t is the reaction time (t = ?) where a is the acceleration (-9.8 m/s2) -0.4 = 0.5(-9.8)(t^2) t = 0.286 seconds (b) using the above equation 5 times when t = 0.14 seconds y = 0.5(-9.8)(.14^2) y = 9.604 cm when t = 0.16 seconds y = 0.5(-9.8)(.16^2) y = 12.544 cm when t = 0.18 seconds y = 0.5(-9.8)(.18^2) y = 15.876 cm when t = 0.20 seconds y = 0.5(-9.8)(.20^2) y = 19.6 cm when t = 0.22 seconds y = 0.5(-9.8)(.22^2) y = 23.716 cm bol