Question

what makes the yardstick test a direct measurement of reaction time? a. the further the yardstick falls, the slower the reaction time. b. the further the yardstick falls, the faster the reaction time. c. yardsticks are created specifically for testing reaction time. d. the yardstick test will give the exact same reaction time every time it is used. please select the best answer from the choices provided. a b c d

Explanation:

• For option A: When using the yard - stick test, the distance \(d\) the yard - stick falls is related to the reaction time \(t\) by the equation \(d = v_0t+\frac{1}{2}gt^{2}\). Assuming the initial velocity \(v_0 = 0\) (the yard - stick is in free - fall at the start of the reaction time measurement), \(d=\frac{1}{2}gt^{2}\). So, \(t=\sqrt{\frac{2d}{g}}\). As \(d\) (the distance the yard - stick falls) increases, \(t\) (reaction time) increases. That is, the further the yardstick falls, the slower the reaction time.
• Option B is incorrect because of the relationship \(t=\sqrt{\frac{2d}{g}}\) (when \(v_0 = 0\)), which shows a positive correlation between \(d\) and \(t\), not a negative one.
• Option C is wrong. Yardsticks are mainly used for measuring length in general, not specifically created just for testing reaction time.
• Option D is incorrect. There are many factors that can affect the reaction time measurement, such as the tester's state (fatigue, distraction etc.), so the yardstick test will not give the exact same reaction time every time.

Answer:

A. The further the yardstick falls, the slower the reaction time.