Projectile Motion Lab Supplemental Questions
1. For the 40 cm trial run, assume an error on the measurement of distance of 0.01 metres and an error for
time of 0.15 seconds. Calculate the highest and lowest possible value for speed.
Calculate the absolute error in speed.
Calculate the relative error for speed.
Calculate the relative error for time and distance.
2. If you did the same calculations for the 60 cm run, what would happen to relative error for distance and
time? Why
3. Assume Δdy is 105 cm and the initial velocity in the y direction is 0. Assume Δd (distance the marble
travels on the table top) is 40 cm and the average time the marble requires to traverse 40 cm is 0.55 seconds.
a) Calculate initial velocity in the x direction, time of fall and Δdx (this is the actual position the ball would
land on).
b) Assume that you made an error when recording time and that you recorded a time less than 0.55 seconds,
such as 0.50 seconds. Based on this error, calculate initial velocity in the x direction, time of fall and Δdx
(this is the position the cup would be placed at).
c) How does an error in time effect the position of the cup relative to where the ball lands?
Theory Questions:
1. A baseball is hit at an angle of 5 degrees with a speed of 70 m/s. The displacement in the y direction is 0
when the ball is caught.
a) Calculate the total time of flight
b) Calculate the displacement of the ball in the x direction when it is caught
c) Calculate the maximum height in the y direction and the displacement in the x direction for which this
occurs