1. The problem statement, all variables and given/known data At time t = 0, a point starts oscillating on the x - axis according to the law x = a sin(ωt). Find the average velocity vector projection (I assume it means magnitude based on previous questions in the book). 2. Relevant equations 3. The attempt at a solution I knew that the average velocity over a large motion will be the same as the average velocity over a 1/4 of an oscillation so I let x = a. Then a = a sin(ωt) ⇒ t = π/2ω and so the average velocity is 2aω/π. However, in the official solution it claims the answer is ((2√2)/3)*aω. I don't see how this makes sense and fear I am either missing something substantial or the official solution is incorrect.