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P. 4315. Two balls of masses m1=0.173 kg and m2=0.2 kg are moving and the direction of their motion is perpendiculer to each other. Their speeds are v1=10 m/s and v2=5 m/s, respectively. After the collision the ball of mass m1 stops. What will the speed of the ball of mass m2 be after the collision?

(4 points)

Google Translation (Sorry, the solution is published in Hungarian only.)

Megoldás. Az ütközés elõtt a két golyó együttes lendülete a merõleges haladási irány miatt $\displaystyle \sqrt{m_1^2v_1^2+m_2^2v_2^2}$. Az ütközés után a teljes lendületet a 2-es golyó viszi el, ezért ennek sebessége $\displaystyle v_2'=\sqrt{\left( \frac{m_1}{m_2} \right)^2v_1^2+v_2^2}\approx 10$ m/s.

Statistics on problem P. 4315.
 171 students sent a solution. 4 points: 106 students. 3 points: 24 students. 2 points: 10 students. 1 point: 26 students. 0 point: 1 student. Unfair, not evaluated: 4 solutions.

• Problems in Physics of KöMaL, February 2011

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