Question
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 half the total length but it falls down if the length projected is slightly more than half the total length. Give reason.

Answer


The centre of mass (CM) of a rectangular block lies in the middle of the block. When the block is projected less than half of its length (CM being over the table), no net force acts on it.
Thus, no net torque acts upon the body.But if the block is projected more than half of its length outside the table (CM being outside the table), gravitational force acts along the CM of the block. This force produces a moment along the edge of the table. This rotates the block, and as a result, it falls down.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

What is the value of modulus of rigidity for a liquid?
If one component of a vector is zero, and other component is not zero then can that vector be zero?
Give the magnitude and direction of the net force acting on.
A drop of rain falling down with a constant speed.
A simple pendulum is a point mass suspended by a light thread from a fixed point. The particle is displaced towards one side and then released. It makes small oscillations. Is the motion of such a simple pendulum a pure rotation? If yes, where is the axis of rotation?
An artificial satellite revolving around the earth does not need any fuel. On the other hand, the aeroplane requires fuel to fly at a certain height.Why?
Why it is easier to wash clothes with soap solution rather than pure water?
Two objects are given, whose initial conditions are different but the relative velocities is zero. Draw the position time diagram for the corners.
A capillary tube of radius 0.50mm is dipped vertically in a pot of water. Find the difference between the pressure of the water in the tube 5.0cm below the surface and the atmospheric pressure. Surface tension of water = 0.075N/m.
The terminal velocity of a copper ball of radius $2.0 mm$ falling through a tank of oil at $20^{\circ} C$ is $6.5 cm s ^{-1}$. Compute the viscosity of the oil at $20^{\circ} C$. Density of oil is $1.5 \times 10^3 kg m ^{-3}$, density of copper is $8.9 \times 10^3 kg m ^3$.
What is the apparent weight of a man of 60kg who is standing in a lift which is moving up with a uniform speed?