mechanics: Quick Facts

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A diagram with labeled vector illustrations. Panel A shows vector addition with two green arrows A and B forming a parallelogram, and their sum C as a red diagonal. Panel B shows vector subtraction, with A and negative B forming resultant D. Panel C demonstrates vector components using angles and projections. Panel D uses the right-hand rule with thumbs to show the direction of the cross product E = A x B and its opposite, -E = B x A.

Two elephants pull a log in opposite directions with equal force, keeping the log stationary to illustrate Newton's law that balanced forces result in no movement.

Two diagrams compare a mass attached between two horizontal springs. In A, the mass m is centered and springs are at rest. In B, the mass is shifted right by distance x, stretching the left spring and compressing the right.

A graph of the function x equals A cosine omega t, showing a cosine wave oscillating between A and negative A along the vertical axis, with horizontal axis marked at pi and 2 pi.

A graph showing damped oscillations, with a red wave decreasing in amplitude over time. The vertical axis is labeled amplitude and the horizontal axis is labeled time. Dashed green lines illustrate the exponential decay envelope.

Two graphs compare projectile motion. Panel A shows a parabolic path starting high on the Z axis and curving downward to the X axis. Panel B shows a parabolic path starting at the origin, rising upward, then curving back down to the X axis, illustrating an initial upward velocity.

A diagram of a simple pendulum showing a mass labeled M suspended by a string of length L from a fixed point, with the pendulum displaced at an angle theta from the vertical and an arc indicating its swing path.

A geometric diagram of a circular segment with radius labeled L, central angle labeled theta, arc length marked as L times theta, and a vertical segment inside labeled L times sine theta.

Five-panel diagram showing a particle's uniform circular motion. Panel A shows position vector r(t) from the origin to a point on a quarter circle, with x, y, and angle theta labeled. Panel B illustrates the change in position vectors and arc length for a small time interval. Panel C shows the velocity vector tangent to the path. Panel D displays velocity vectors at two points. Panel E shows the change in velocity vector and acceleration vector a(t) pointing toward the circle's center. All vecto

Diagram showing the Sun at the center with the Earth orbiting around it. Arrows indicate the gravitational force pulling Earth toward the Sun and the centripetal acceleration, while another arrow shows Earth's instantaneous velocity tangent to its orbit.

How rockets work: Newton's third law of motion explained

Newton's law of gravitation: Apollo 15 gravitation experiment

How does Earth orbit around the Sun?

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Topics

rock mechanics fracture mechanics classical mechanics continuum mechanics Lamé constant fluid mechanics mechanics of solids quantum mechanics Celestial mechanics relativistic mechanics optics Cosmology thermodynamics electronics acoustics biophysics atomic physics cryogenics tribology psychophysics

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Key People

Self-portrait of Leonardo da Vinci drawn in red chalk, showing an elderly man with long hair and a flowing beard, with a serious, contemplative expression.

Leonardo da Vinci

Italian artist, engineer, and scientist

Galileo

Galileo

Italian natural philosopher, astronomer, and mathematician

Portrait of Archimedes by Giuseppe Nogari shows an elderly man with white hair and beard, holding a compass, gazing downward, set against a dark background.

Archimedes

Greek mathematician and inventor

Jean Le Rond d'Alembert.

Jean Le Rond d’Alembert

French mathematician and philosopher

Henri Poincaré, 1909.

Henri Poincaré

French mathematician

Lagrange, Joseph-Louis, comte de l'Empire

Joseph-Louis Lagrange, comte de l’Empire

French mathematician

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Heron of Alexandria

Greek mathematician

Ludwig Prandtl.

Ludwig Prandtl

German physicist

Evangelista Torricelli

Evangelista Torricelli

Italian physicist and mathematician

Gaspard-Gustave de Coriolis

Gaspard-Gustave de Coriolis

French physicist

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Charles-Eugène Delaunay

French astronomer

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A.C. Ewing

British philosopher and educator

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Giovanni Ceva

Italian mathematician and engineer

Italian physicist Guglielmo Marconi at work in the wireless room of his yacht Electra, c. 1920.

All About Physics Quiz

Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.

Physics and Natural Law