Bennett Mechanical Structures and Center of Gravity Questions and Answers

Question 1

Four objects are made of the same uniform material. Which object is the most stable and least likely to tip over if placed on a flat, level surface?

Accepted Answer

A short, wide cone resting on its base

Answer

A tall, thin cylinder standing on its end

Answer

A perfect sphere

Answer

A tall pyramid balanced on its point

Question 2

A perfect 'L' shape is created by joining two identical, uniform rectangular blocks of wood at their ends. Where is the center of gravity of the combined 'L' shape located?

Accepted Answer

In the empty space inside the 'corner' of the L.

Answer

Exactly at the point where the two blocks are joined.

Answer

In the geometric center of the vertical block.

Answer

In the geometric center of the horizontal block.

Question 3

Which of the following geometric shapes, when constructed with beams of equal length and joined by pins at its vertices, forms the most rigid structural element?

Accepted Answer

A triangle

Answer

A square

Answer

A pentagon

Answer

A rectangle

Question 4

To ensure maximum stability and prevent rolling over during a sharp turn, where should a single, heavy crate be placed on the flatbed of a truck?

Accepted Answer

As low and as close to the center of the truck bed as possible.

Answer

As far forward as possible, against the cab, and stacked high.

Answer

On one side, directly over the rear wheels.

Answer

As far back as possible on the tailgate.

Question 5

A horizontal cantilever beam is securely fixed into a wall at one end and extends outwards. If a heavy weight is hung from the free end, where will the beam experience the greatest bending stress?

Accepted Answer

At the point where it is fixed to the wall.

Answer

At the free end, where the weight is attached.

Answer

Exactly in the middle of its length.

Answer

The stress is uniform along the entire length.

Question 6

A tall, rectangular box is placed on a flat plank. The plank is then slowly tilted. At which point will the box begin to tip over?

Accepted Answer

When a vertical line drawn downward from the box's center of gravity falls outside its base of support.

Answer

When the angle of the plank exceeds 45 degrees.

Answer

When the top corner of the box is higher than the bottom corner.

Answer

When the force of friction is no longer great enough to prevent sliding.