일반물리학 1 — Center of Mass and Linear Momentum: Problem 74

74 A force $\vec{F}$ acts on two particles of masses $m$ and $4.0m$ moving at the same speed but at right angles to each other, as shown in Fig. 9-62. The force acts on both the particles for a time $T$. Consequently, the particle of mass $m$ moves with a velocity $4v$ in its original direction. (a) Find the new velocity $v'$ of the other particle. (b) Also find the change in the kinetic energy of the system.