Question

A stick is resting on a concrete step with 2/9 of its length hanging over the edge. A single ladybug lands on the end of the stick hanging over the edge, and the stick begins to tip. A moment later, a second, identical ladybug lands on the other end of the stick, which results in the stick coming momentarily to rest 41.3° from the horizontal. If the mass of each bug is 3.60 times the mass of the stick and the stick is 16.3 cm long, what is the magnitude of the angular acceleration of the stick at the instant shown?

Answer 1

Formula for Angular acceleration:

where,

Angular acceleration

net torque

moment of inertia.

so for total torque and moment of inertia is to find

counter-clockwise as the negative angular direction so we use negitive sign.

The weight of the stick can be assumed about its centre.

so net Torque is

moment of inertia

From the standard formula, the moment of inertia of the stick about its centre.

By the parallel axis theorem, the moment of inertia, I, of the stick about the pivot point is.

so,