The picture below shows a gravel shooter, a fast moving conveyor belt that shoots the gravel to the desired point on the construction site. Perform some measurements on the photograph and calculate the speed with which the gravel leaves the end of the conveyor belt.
[Figure: Photograph of gravel shooter showing projectile motion]
a) Estimate the uncertainty of your answer.
b) Estimate how much the air drag (friction) affects the distance to which gravel is shot.
c) What is the average drag force on the gravel?