Investigating Unexpected Results in Elementary Experiment

Thread starter nomadreid
Start date Jan 20, 2023
Tags

Elementary Experiment Hooke's law

In summary, the conversation discusses an elementary experiment involving a slingshot and projectile. The experiment was done successfully with secondary school classes, but when given to a homeschooling student in a different country, the results were off by a factor of two. The experiment assumes that the rubber strip in the slingshot follows Hooke's Law and involves finding the spring constant (k) experimentally, measuring the angle and length of the projectile, shooting it multiple times, and calculating the theoretical and measured horizontal distances. The calculations were correct, but the most likely reason for the discrepancy is the value of k. One suggestion is to measure/calculate k multiple times to account for variability in the rubber strip.

Jan 22, 2023

nomadreid

Gold Member

haruspex said:

You mean (v2*sin2A)/g.

oops, yes. o:)

Apologies, .

haruspex said:

Also, it looks like at release the projectile is about 2.7cm above the ground, which should add about 5cm to the range.
Feeding 111cm into the formula I get 3.7m/s.

OK, that makes a lot more sense now. Thanks very much, haruspex.

erobz said:

Ok, so this is where the actual geometry of the slingshot could come into play.

Thanks again, erobz. I presume it is OK for me to use your diagram (but with numbers, since an equation with that many variables is a bit much for a 13-year old) in explaining some of these ideas in my next lesson with the student?