# Massless particle revolving in a circle

Given: A massless particle revolving in a circle with a rotational velocity = (2+sin(a))
To Find: Y-axis acceleration
Method #1 (from rotational acceleration)
Y-axis acceleration = (2+sin(a))(cos(a))^2
Method #2 (from Y-axis velocity)
Y-axis acceleration = (2+sin(a))(cos(a))^2-(sin(a))(2+sin(a))

Which Y-axis acceleration is correct and why?

Can someone explain this?

Related Introductory Physics Homework Help News on Phys.org
HallsofIvy
Homework Helper
rotational velocity = (2+sin(a))
What does this mean? Is a an angle? If so what angle?
And what do you mean by "y-axis" acceleration? Are we to assume that the circle is in the xy-plane and you are looking for the y-component of acceleration?

HallsofIvy said:
What does this mean? Is a an angle? If so what angle?
And what do you mean by "y-axis" acceleration? Are we to assume that the circle is in the xy-plane and you are looking for the y-component of acceleration?
You tell me. I have no clue what they are asking. Gokul43201
Staff Emeritus