9TH GRADE · CURVILINEAR MOVEMENT AND BALANCE
Balance and center of gravity
Moments of forces, center of gravity and stability of balance.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Center of gravity
The point of application of the resultant forces of gravity acting on parts of the body in a uniform field.
Its position is found by suspension or by symmetry, and in a hollow body the point may be outside the substance.
Equilibrium conditions
For the body to be in equilibrium, both the resultant forces and the total moment of forces relative to the axis are equal to zero.
The first condition excludes translational acceleration, the second - angular acceleration.
Equilibrium stability
Equilibrium is stable if a small deviation causes an impact that returns the body to its original position.
The low center of gravity and wide support area increase stability as long as the vertical center of gravity runs inside the support.
Physical quantities
moment of force
The product of the force on its arm relative to the axis.
Unit: newton meter ·
Shoulder of power
The shortest distance from the axis to the line of action of the force.
Unit: meter ·
Lesson formulas
moment of force
The moment of force is equal to the product of force and its arm.
Equilibrium of moments
In equilibrium, the moments of forces rotating the body in opposite directions are equal.
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.