Mathematical and Physical Journal
for High Schools
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Problem P. 4556. (September 2013)

P. 4556. There is a spring of spring constant D=240 N/m between two easily rolling carts of masses m1=2 kg and m2=3 kg. The spring is kept at a compressed position by a thin thread and the compression of the spring is =15 cm. The common speed of the two carts is v=2 m/s. What will their velocities be after the break of the thread?

(4 pont)

Deadline expired on October 10, 2013.

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

Megoldásvázlat. A tömegközépponti rendszerben a kiskocsik $\displaystyle u_1=1{,}27~$m/s és $\displaystyle u_2=0{,}85~$m/s sebességgel lökődnek szét. A fonál elszakadása után kiskocsik (az eredeti haladási iránytól függően)

$\displaystyle v_1=v+u_1=3{,}27~{\rm m/s}; \qquad v_2=v-u_2=1{,}15~{\rm m/s},$

vagy

$\displaystyle v_1=v-u_1=0{,}73~{\rm m/s}; \qquad v_2=v+u_2=2{,}85~{\rm m/s}$

sebességgel fognak mozogni.

Statistics:

 137 students sent a solution. 4 points: 55 students. 3 points: 22 students. 2 points: 11 students. 1 point: 23 students. 0 point: 26 students.

Problems in Physics of KöMaL, September 2013