# BookRiff

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## What is a precessional cycle?

In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body’s rotational axis. In particular, it can refer to the gradual shift in the orientation of Earth’s axis of rotation in a cycle of approximately 26,000 years.

What is meant by gyroscopic precession?

Torque-induced precession (gyroscopic precession) is the phenomenon in which the axis of a spinning object (e.g., a gyroscope) describes a cone in space when an external torque is applied to it. The phenomenon is commonly seen in a spinning toy top, but all rotating objects can undergo precession.

### What is Precessional angular motion?

Quick Reference. A form of motion that occurs when a torque is applied to a rotating body in such a way that it tends to change the direction of its axis of rotation.

What is Precessional angular velocity?

The precessional angular velocity is given by ωP=rMgIω ω P = r M g I ω , where r is the distance from the pivot to the center of mass of the gyroscope, I is the moment of inertia of the gyroscope’s spinning disk, M is its mass, and ω is the angular frequency of the gyroscope disk.

#### What does precession of the equinox refer to?

: a slow westward motion of the equinoxes along the ecliptic caused by the gravitational action of sun and moon upon the protuberant matter about the earth’s equator.

What causes orbital precession?

Precession – As Earth rotates, it wobbles slightly upon its axis, like a slightly off-center spinning toy top. This wobble is due to tidal forces caused by the gravitational influences of the Sun and Moon that cause Earth to bulge at the equator, affecting its rotation.

## What causes precession of a gyroscope?

Why does precession occur? The weight that is hung of the gyroscope (represented by a cross on the diagram to the left) is offset from the center of mass of the gyroscope and stand. It is this offset of forces which causes precession.

What is rigidity in space and precession?

When the wheel is rotating, the gyroscope has two special properties: rigidity and precession. Rigidity is the ability of the gyroscope to maintain its axis pointing in a fixed direction in space, unless subjected to an external force (also known as gyroscopic inertia).

### What causes precession?

Precession is caused by the gravitational influence of the Sun and the Moon acting on Earth’s equatorial bulge.

What does precession mean in physics?

precession, phenomenon associated with the action of a gyroscope or a spinning top and consisting of a comparatively slow rotation of the axis of rotation of a spinning body about a line intersecting the spin axis. The smooth, slow circling of a spinning top is precession, the uneven wobbling is nutation.

#### What is precession and what are its effects?

Precession refers to a change in the direction of the axis of a rotating object. The revolution of a planet in its orbit around the Sun is also a form of rotary motion. (In this case, the combined system of Earth and Sun is rotating.) So the axis of a planet’s orbital plane will also precess over time.

Why is the precession of the equinoxes important?

The projection onto the sky of Earth’s axis of rotation results in two notable points at opposite directions: the north and south celestial poles. Because of precession, these points trace out circles on the sky. Today the north celestial pole points to within just 1° of the arc of Polaris.