A small blob of putty of mass m falls from the ceiling and lands on the outer ri
ID: 1911218 • Letter: A
Question
A small blob of putty of mass m falls from the ceiling and lands on the outer rim of a turntable of radius R and moment of inertia I0 that is rotating freely with angular speed ?0 about its vertical fixed-symmetry axis. (Use any variable or symbol stated above as necessary. (a) What is the postcollision angular speed of the turntable-putty system? ?f = ???? (b) After several turns, the blob flies off the edge of the turntable. What is the angular speed of the turntable after the blob's departure? ? = ?????Explanation / Answer
use conservation of angular momentum ang momentum before = ang momentum after ang momentum = I w I for a disc = 1/2 MR^2 before: 1/2 MR^2 w1 after: I = 1/2 MR^2 + mR^2 so 1/2 MR^2 w1 = (1/2 MR^2 + mr^2)w2 solve for w2