1. The problem statement, all variables and given/known data Four particles with masses 2 kg (top left corner), 3 kg (bottom left corner), 4 kg (bottom right corner), and 5 kg (top right corner) are connected by rigid rods of negligible mass. The origin is centered on the center of the rectangle of sides 0.8 length and 0.6 breadth. If the system rotates in the XY plane about the z axis with angular speed of w=5 rad.sec. What is the rotational kinetic energy. 2. Relevant equations I=mr^2 and KE rot = .5 Iω^2 3. The attempt at a solution I can use the formulas but the main problem for me is to determine the axis of rotation. Why did it mention both XY plane and Z axis. Which one exactly is the axis of rotation. Moreover, if it is the Z axis, how can we get R??? Thanks to whoever contributes.