Question

When visiting some countries, you may see a person balancing a load on the head. Explain why the center of mass of the load needs to be directly above the person’s neck vertebrae.

Short answer

The center of mass of the load is on the person’s neck vertebrae makes the equilibrium.

Step-by-step solution

Mass

The mass of a body is used to determine how much matter it contains. Kilogram is the SI unit of mass (kg). A person's mass does not alter over time.

Explanation

When the center of mass of the object on the person’s head is along the same line, then the force of weight and the normal reaction on the weight acts on the same line. Therefore there is no torque experienced by the person and the weight.

The condition is shown in the diagram below:

When the center of mass of the weight on the head and the center of mass of the neck vertebrae are not along same line, the weight produces a clockwise torque about the pivot.

The condition is shown below in the diagram:

The reaction produces a clockwise torque about the pivot. Thus, the net torque is not zero and the equilibrium is not established.