Answer
See work.
Work Step by Step
The meterstick has a constant downward acceleration. We know the initial velocity of 0 m/s and the displacement. Use the kinematics formulas for constant acceleration to find the reaction time.
a. Let the downward direction be positive. The meter stick has zero initial velocity and $a_y=9.80m/s^2$. Let d be the distance the meterstick falls.
Use $y-y_o=v_{oy}t+0.5at^2$
$d= 0+(4.90m/s^2)t^2$
$t=\sqrt{\frac{d}{4.90m/s^2}}$
b. Evaluate for d = 0.176 m to find a reaction time of 0.190 s.
