Question

A 2.25

Answer 1

To solve the problem we can use the conservation of energy. If M (=W/g) is the mass of the elevator, m the mas of the couterweight and m_p the mass of the polley, and we will use the floor level as reference. The equation we get is:

,                        (1)

where h₀ is the original height of the counterweight, and I the inerce moment of the polley:

,                           (2)

Also, the relation of the linear and angular speeds is:

                           (3)

Then, substituting all in the equation (1) we get:

,      (4)

or

            (5)

We can solve this equation to find the acceleration from the relation:

                       (6)

Then:

,                    (7)

That, has a known value:

               (8)

Solving eq (5) for m we get:

substituting all values:

.

or

.

The tensi