Motion of Two Balls Connected by a Rod

t

m

1

m

2

v

x

v

y

ω

tracks

A rod of negligible mass connecting two balls is thrown into the air. The masses of the balls are

m

1

and

m

2

, the horizontal and vertical velocities are

v

x

and

v

y

, and the angular velocity is

ω

. The system exhibits a combination of translational and rotational motion that produces a rippled path. The blue curve follows the center of mass, which moves in a parabolic trajectory. The red curve follows one of the balls as it spins around the center of mass.