Hi there!
Recall the equation for angular momentum:
L = Angular momentum (kgm²/s)
I = Moment of Inertia (kgm²)
ω = angular velocity (rad/s)
We know that the Moment of Inertia of a solid cylinder is equivalent to:
M = mass (kg)
R = radius (m)
Plug in the givens to solve for the moment of inertia. Remember to divide the diameter by 2 for the radius, and to convert to meters.
We can rearrange the equation of angular momentum to solve for mass.