In an experiment to determine the acceleration due to gravity, one student drops a tennis ball out of the school’s third floor window. another student starts a timer when the first student lets go and stops the timer when the ball hits the ground. they conduct the experiment once and record the data. is this a valid experiment, why or why not? a. no, it is not valid because the short distance means there will be a lot of error due to the student’s reaction time. b. no, it is not valid because they are only dropping one item. c. yes it is valid. d. no, it is not valid because they did not have any repeat trials.