Question

The figure below represents a small, flat puck with mass m = 2.32 kg sliding on a frictionless, horizontal surface. It is held in a circular orbit about a fixed axis by a rod with negligible mass and length R = 1.16 m, pivoted at one end. Initially, the puck has a speed of v = 4.57 m/s. A 1.00-kg ball of putty is dropped vertically onto the the puck from a small distance above it and immediately sticks to the puck.

(a) What is the new period of rotation? ______ s

Answer 1

using conservation of angular momentum, Li = Lf, & L=mvr,

mrVi=mrVf

(2.32)(1.16)(4.57)=(2.32+1.00)(1.16)(V final)

solving for final velocity you get 3.2
then to convert the velocity into a period you use T=2piR/v
plug in your velocity & get 2.05