1. The problem statement, all variables and given/known data Attached. 2. Relevant equations Tangenital acceleration=r*alpha 3. The attempt at a solution I thought it was just simply r*alpha=2*20=40 (choice A), but the answer key says choice B. I'm not really sure where I could have went wrong or its possible that there is a mistake in the answer key. Any insight would be very helpful. Thanks.