This is the rate of acceleration of any object falling under the sole influence of gravity.

Little g is known as the acceleration of objects due to Earth's gravitational field near its surface. This is the average value for objects very small compared to the size of the Earth itself. This average value is approximately 9.80665m/s².

The actual acceleration on an object due to Earth's gravity changes with the object's distance from the Earth due to the inverse square nature of Newton's law of universal gravitation, but within the range of heights we normally work with (consider the range of heights from sea level to the tip of Mount Everest), this change is so small that we can assume the acceleration to be constant. This lends to some nice simplifications we can use in physics and engineering problems concerning everyday situations that happen on Earth.

no. dot product   =0 when vecs at right angles