A puck of mass m = 55.0 g is attached to a taut cord passing through a small hol

Question

A puck of mass m = 55.0 g is attached to a taut cord passing through a small hole in a frictionless, horizontal surface (see figure below). The puck is initially orbiting with speed vi = 1.70 m/s in a circle of radius ri = 0.310 m. The cord is then slowly pulled from below, decreasing the radius of the circle to r = 0.110 m.

(a) What is the puck's speed at the smaller radius?
? m/s

(b) Find the tension in the cord at the smaller radius.
? N

(c) How much work is done by the hand in pulling the cord so that the radius of the puck's motion changes from 0.310 m to 0.110 m?
? J

Explanation / Answer

a) Angular momentum is conserved:
V1*r1 = V2*r2 ? V2 = V1[r1/r2] = 4.79 m/s

b) T = m*a = m*V2

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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