In an experiment to determine the acceleration due to gravity, one student holds a pencil at arm’s length and drops it. another student starts a timer when the first student lets go and stops the timer when the pencil hits the ground. they repeat this several times and take an average. is this a valid experiment, why or why not?

a. no, it is not valid because they are only dropping one item.
b. no, it is not valid because taking the average will increase rounding error.
c. yes it is valid.
d. no, it is not valid because the short distance means there will be a lot of error due to the student’s reaction time.