P5: Quiz 19 – Answers
a) 0.2 seconds to 0.9 seconds
b) Any two factors from drugs, tiredness, age, distractions, caffeine etc.
2) The ruler dropping experiment involves two individuals. The person being tested rests their forearm on a table with their hand slightly over the edge of the table. The other individual who is not being tested holds a ruler vertically between the thumb and index finger of the individual being tested. The zero marking on the ruler should be in line with the thumb and index finger. The ruler is then let go randomly and the student with their arm on the table catches the ruler as quickly as possible. We record the number on the ruler where the thumb and index finger are; this number is the distance travelled by the ruler. We repeat the experiment a few times and work out the mean. We can then work out the reaction time from the mean distance and acceleration due to gravity by using two physics equations.
3)
a) 2.8 m/s
b) 0.28 or 0.29 seconds
4) 0.32 or 0.33 seconds
5)
a) A computer experiment where students are asked to click the mouse or press a key when a stimulus appears on the computer screen
b) We obtain a more accurate value for reaction time. This is because the computer program will randomly generate the stimulus, which removes the possibility of the individual being tested anticipating when the ruler will be dropped. Also, the computer is able to measure reaction times more accurately (to milliseconds). Furthermore, there is no possibility of human error when using a computer
1)
a) What is the typical range of reaction times for individuals?
b) Give 2 factors that affect the reaction times of individuals.
2) One way that we can investigate reaction times is to use the ruler dropping experiment. Discuss how the ruler dropping experiment works.
You do not need to go into detail about the calculations that are used to calculate reaction times in the ruler dropping experiment.
3) Some students complete the ruler dropping experiment. A student catches the ruler after it has dropped by 39 cm. For both of the questions below, use acceleration due to gravity as 9.8 m/s2.
a) Calculate the final velocity of the ruler. Give your answer to 2 significant figures.
b) Calculate the reaction time. Give your answer to 2 significant figures.
4) Some students complete the ruler dropping experiment. A student catches the ruler after it has dropped by 52 cm. Calculate the reaction time. Give your answer to 2 significant figures. Use acceleration due to gravity as 9.8 m/s2.
5)
a) What is an alternative experiment that we can use to measure the reaction time of an individual?
b) Discuss the benefits of using this experiment compared to the ruler dropping experiment.