Science Buddies: "Ask an Expert"

Please explain where the "second" comes from in the math equation for the Gauss Rifle project. Gauss Rifle for my science project this year. I don't understand the math. The instructions indicate the velocity (m/second) is equal to horizontal distance between the table and the ball in meters times the square root of gravitational acceleration (meters/seconds squared) divided by 2 times the height of the table in meters. Where do you get the seconds from in this equation? Should there be a step that we measure the the time it took to leave the rifle to when it lands??

dwroe - From the moment the ball leaves the edge of the table, it will accelerate to the floor at the rate of gravitational force, or 9.8 meters per second per second. It is accelerating downward! This experiment is calculating the initial velocity of the ball bearing by calculating the horizontal distance it travels as it accelerates to the floor. The 'seconds' you are referring to is just part of the expression in the gravitational force of 9.8 M/seconds-squared. To use the equation simply enter the horizontal measurement you made and forget about 'seconds' at this point. Your result will be velocity in the form of Meters/second.

Rick Marz

Thank you so much!