Mathematical and Physical Journal
for High Schools
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# Problem P. 4288. (November 2010)

P. 4288. A spring of length , is hang and when an object is attached to it, its length changes to 2. (The extension of the spring is proportional to the force and its mass is negligible.) When the object, attached to the spring, undergoes uniform circular motion along a horizontal path, the length of the spring is L What are the radius of the circle and the angular speed of the object?

(4 pont)

Deadline expired on December 10, 2010.

Sorry, the solution is available only in Hungarian. Google translation

Megoldás. A szögsebesség $\displaystyle \sqrt{\left(\frac{1}{\ell}-\frac{1}{L}\right)g}$, a körpálya sugara pedig $\displaystyle \frac{L}{L-\ell}\sqrt{L(L-2\ell)}.$

### Statistics:

 131 students sent a solution. 4 points: 55 students. 3 points: 13 students. 2 points: 25 students. 1 point: 18 students. 0 point: 15 students. Unfair, not evaluated: 5 solutions.

Problems in Physics of KöMaL, November 2010