A penny is placed on the outer edge of a disk (radius = 0.153 m) that rotates ab

Question

A penny is placed on the outer edge of a disk (radius = 0.153 m) that rotates about an axis perpendicular to the plane of the disk at its center, like a record or a CD. The period of the rotation is 1.97 s.

(a) What, if anything, is producing the centripetal force that enables the penny to rotate along with the disk?
b) The centripetal force depends on the speed at which the penny is moving. On what does this speed depend? c) What is the algebraic expression for the minimum coefficient of static friction ?s necessary to allow the penny to rotate along with the disk? Express your answer in terms of the radius r of the disk, the magnitude g of the acceleration due to gravity, and the period T of the rotation.d)What is the minimum coefficient of static friction ?s necessary to allow the penny to rotate along with the disk?

Explanation / Answer

a) The friction between the penny and the disk is producing the required centripetal force to rotate the penny along with the disk.

b) The speed depends on the radius and angular velocity of the disk.

c)the centripetal force on the penny=mv2/r=friction force=mg

T=2r/v

v=2r/T

m*(2r/T)2/r=mg

=42r/(T2g)

d) putting given values, =0.159

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.