A coin with a diameter of 2.40 cm is dropped on edge
onto a horizontal surface. The coin starts out with an initial
angular speed of 18.0 rad/s and rolls in a straight line
without slipping. If the rotation slows with an angular acceleration
of magnitude 1.90 rad/s2,

Question

A coin with a diameter of 2.40 cm is dropped on edge
onto a horizontal surface. The coin starts out with an initial
angular speed of 18.0 rad/s and rolls in a straight line
without slipping. If the rotation slows with an angular acceleration
of magnitude 1.90 rad/s2,

anonymous · Answer

I think you forgot some details.

anonymous · Answer

Assuming your question finishes with "how far does the coin roll before coming to rest?", you should use the equation $$ω^2 = ω_i^2 + 2α∆θ$$