The bola is a weapon used by gauchos for entangling animals. It consists of three balls of stone or iron connected by things. The gaucho whirls the bola in the air and hurls it at the animals. What can we say about its motion?

Explanation

Consider a bola with masses `m1,m2, and m3`. The balls are pulled by the binding thong and by gravity. (We neglect air resistence). Since the constraining forces on the instantaneous positions of all three balls, it is a real problem even to write the equation of motion of one ball. However, the total momentum obeys the simple equation.
`(dP)/dt=F_(ext)=f_1^(ext)+f_2^(ext)+f_3^(ext)=m_1g+m_2g+m_3g`
or `(dP)/dt=Mg`