"A coin C of mass .0050 kg is placed on a horizontal disk at a distance of .14 m from the center, as shown above. the disk rotates at a constant rate of counterclockwise direction as seen from above. The coin does not slip, and the time it takes for the coin to make a complete revolution is 1.5 seconds."

"The figure below shows the disk and coin as viewed from above. Draw and label vectors on the figure to show the instantaneous acceleration and liner velocity vectors for the coin when it is at the position show"

Graphic of a circle, the disk, with a little circle, the coin, on top of it with a vector showing movement going counter clockwise.

I think I've got this one figured out. The acceleration is going inward and the coin is moving outwards. Friction is also pulling the coin in.

b." Determine the speed of the coin."

Pretty sure you just need to do 2πr/T to get the velocity.

c. The rate of rotation of the disk is gradually increased. The coefficient of static friction between the coin and the disk is .50. Determine the linear speed of the coin when it just begins to slip.

I dont relie know what to do on this one. Would I do something like ∑F = Ft = mv^2/r then µmg = mv^2/r then I would solve for v?

d. "If the experiment in part (c) were repeated with a s second, identical coin glued to the top of the first one how would this affect the answer to part (c)? Explain your reasoning.

so if µmg = mv^2/r then the m's cancel out so mass is negligible. Nothing changes.