What is sign convention in gravity
Answers
The acceleration due to gravity, g, is in a direction toward the ground. The same is true of the force of gravity, F = mg.
Both g and F can be considered vectors, which are geometric representations indicating both magnitude and direction. Vectors are typically drawn as arrows, with their length proportional to their magnitude. The magnitude of g is 9.8 m/s2 or 32 ft/s2.
Since both the acceleration due to gravity and the force of gravity are downward, we use the convention for our gravity equations that downward vectors are positive (+). Likewise, upward vectors are negative (−).
In essence, this is flipping the x-y or Cartesian coordinate system, such that the +y-axis points down and the −y-axis points up.
This convention affects the other vectors used in gravity equations, which include:
Displacement: y and xVelocity: v