I have been stuck on these forever...but here goes: 1st question: A tire placed on a balancing machine in a service station starts from rest and turns through 5.5 revs in 1.0 s before reaching its final angular speed. Assuming that the angular acceleration of the wheel is constant, calculate the wheel's angular acceleration. I know that you have to convert 5.5 rev into pi rad, but I keep getting the wrong answer (this is on an online HW assignment). work: formula aavg = (w2-w1)/(t2-t1) 5.5 x 2 pi = 34.5575 pi rad (34.5575 - 0) / (1.0 s) = (I get it wrong here) ---------- 2nd question (this one makes me angrier!) The Emerald Suite, a revolving restaurant at the top of the Space Needle in Seattle, Washington, makes a complete turn once every hour. What is the tangential speed of a customer sitting 16.0 m from the restaurant's center? Ok, I know the formula and setup, but am getting stuck on converting the rotation of the restaurant into what I need: is it rev/s, rev/min? And then do I multiply by 2 pi? The formula is this: at = ra my work: 1 rev/hr = .0166 rev/min = 2.766e-4 rev/sec 2.766e-4 x 2 pi = .0017 rad x 15 s = .0255 m/s (wrong answer it says) ------ Any help would be greatly appreciated - thank you!