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Snow Day Momentum


For the snow day blog, I decided to test two different types of inelastic collisions with snowballs.
The first video demonstrates an inelastic collision in which a snowball of 0.25kg hits a wall.
In this inelastic collision, the 0.25kg snowball travels at 1.8m/s and impacts the wall. The snowball breaks into pieces and transfers 0.45 kg*m/s to the wall which is not noticeably moved(high quality wall, cedar shingles, can't beat it).

This second video demonstrates a similar collision in which another 0.25kg snowball hits a stick and knocks the stick off of two cones.
This screenshot shows the trajectory of the snowball and stick as the kinetic energy is transferred from the former to the latter.
If we use the momentum formula of
m1v1+m2v2=m1v1f+m2v2f
we can calculate the mass of the stick that was hit based on this data and then draw conclusions about energy loss.

The data shows that the snowball being thrown had a velocity of 1.8m/s and the stick after being hit had a velocity of 0.75m/s.
0.25*1.8+0*m2=0.25*0+m2*0.75
0.45=m2*0.75
m2=0.6kg.
If this collision is assumed to have been elastic (which it was not) then the mass of the stick is estimated to be 0.6kg. This collision is not elastic as can be proven through observation- the snowball broke on impact and the majority of the snowball was distributed in pieces and only glanced off of the stick. Therefore, not all of the momentum of the snowball was transferred to the stick. This means that the stick likely weighed less than is predicted by this experiment. In practice, I found and used a stick that was approximately the same mass as the snowball to see how the inelastic nature of the collision would impact the mass calculation. 

Overall, the experiment resulted in the finding that when a collision that is not elastic but has some elastic properties is falsely interpreted as an elastic collision, data results can be skewed and will likely be inaccurate. The degree to which these calculated results are inaccurate reflects the elasticity of the collision.





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