Question

In 1980, over San Francisco Bay, a large yo-yo was released from a crane. Suppose the yo-yo was 153 kg, and it consisted of two uniform disks of radius 35.4 cm connected by an axle of radius 3.19 cm. What was the magnitude of the acceleration of the yo-yo during (a) its fall and (b) its rise? (c)What was the tension in the cord on which it rolled?

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First two parts, the answer is in m/s^2
Third is in N
thanks

Answer 1

find the moment of inertia for the two disks (each has half the mass).
tension*radius= momentinertia*angular acceleartion

and tension= mg-ma=mg-m*angacceleration*r

so you have two equations, two unknowns, solve for tension, and angular acceleartion.

on the way up,
tension*radius=momentinertia*angularacceleration

tension= mg+ma=mg+m(angaccleration*r

Answer 2

The mass or moment of the axle must be specified because its moment of inertia affects the answer.