Conservation of Momentum Blog

Conservation of Momentum Blog

Joseph McGinn

For this blog, I decided to demonstrate conservation of momentum using two golf balls. I used two Nike golf balls, exactly the same size and mass. 

First, I laid a ruler on my kitchen countertop. The ruler, which is in inches, is approximately 0.3048 meters long. I chose my kitchen counter top because it is very slippery and the golf balls would feel the least amount of friction from it. I rolled the two golf balls at one another, trying to keep their paths in a straight line. 

I then used Logger Pro to find the positions of the balls. I then graphed the x position vs time for each golf ball, before and after the collision. Then, I found the slope of the graph which is the velocity of the ball. 

Left Golf Ball Initial Velocity

1.118m/s

Left Golf Ball Final Velocity

-0.1557 m/s

Right Golf Ball Initial Velocity 

-0.3425 m/s

Right Golf Ball Final Velocity

0.8728 m/s

From there I used the equations P = mass times velocity and P(initial)=P(Final)

M*V(left initial) + M*V(right initial)= M*V(left final) +M*V(right final)

the mass of the golf ball is approximately 0.0459 Kg

0.0459(1.118) + 0.0459(-0.3425)= 0.0459(-0.1557) + 0.0459(0.8728)

0.035=0.033

These two values are roughly 0.002 Kg*m/s off

The error in my calculations can be equated to the fact that I probably made small errors in marking the balls in Logger Pro and my measurements will never be exact. 

Kinetic Energy Lost

KE lost = KE initial - KE final

((left initial)+ (right initial))  - ((left final)+ (right final))

=

0.01334 J Lost 

This shows an error in calculations and measurements because in an elastic collision the KE should be conserved