When is an object in motion considered to be a point object?

Can the displacement of a particle be zero when the distance travelled is not zero?

Mohan and Virender were discussing the following problem: $A$ boy kicks a football high into the air. He runs and catches the football before it hits the ground. Which of the two,the boy or the football,has had greater displacement? Mohan was of the opinion that the football has travelled into the air and back,while the boy and the ball have covered the same displacement. Virender told him that it is not true. Both of them discussed and sorted the matter between them.
$(a)$ Who do you think is right,Mohan or Virender?
$(b)$ What are the values you see in Raman?

State whether the following statement is true or false:
Motion along a curved line is called translatory or rectilinear motion.

$A$ farmer moves along the boundary of a square field of side $10 \, m$ in $40 \, s$. What will be the magnitude of displacement (in $m$) of the farmer at the end of $2 \, min \; 20 \, s$ from his initial position?

Name a physical quantity that essentially changes as a body moves.