A rectangular brick is kept on a table with a part of its length projecting out. It remains at rest if the length projected is slightly less than slightly half the total length but it falls down if the length projected is slightly more than half the total length. Give reason.
Answers
Correct Reason ⇒ The weight or the Force of the Gravity of the projected part produces a torque that will tend to overturn the brick about the edge of the table while the weight of the part on the table sometimes produces a torque that will tend to restore the brick from overturning.
Let us Assuming that the uniform density of the brick in the first case, the weight of projected part will be less than the weight of the part on the table.
Also, the distance of the line of action of the weight of the projected part from the edge of the table is also less in comparison to the other part.
Thus, the overturning torque, in this case, will be less than the restoring torque. Thus, the brick remains at rest.
The situation is just reverse in the second case where the overturning torque is greater than the restoring torque, so the brick overturns and falls.
Hope it helps.