Question

What is meant by positive, negative or zero displacement?

Answer 1

The displacement of a body in any direction is given by,

Displacement, d = Final position - Initial position = (x2-x₁) The final position and the initial position are described either relative to each other or to a fixed reference point.

Depending upon the locations of the initial and the final positions, the displacement may be negative, zero or positive. 

• When x₂ is greater than x₁, i.e., x2 > x₁, then ܙ(x₂-x₁) = positive

i.e., the displacement of the body is positive. Thus,

The displacement of a body is positive if its final position lies on the right (on the xx'-axis) of its initial position or above its initial position on the yy'-axis.

•  When x₂ is less than x₁, i.e., x² =x₁, then  d =(x₂-x₁) = negative

i.e., the displacement of the body is negative. Thus,

The displacement of a body is negative if its final position is on the left of its initial position on the x x'-axis or below its initial p position on the y y'-axis.

"When x₂ is equal to x₁, i.e., x₂ = x₁, then d = (x₂ - x₁) = 0 i.e., the displacement of the body is zero. This means that the initial and the final positions of the body are the same, i.e., the body returns to its initial (starting) position (Fig. 1.9).