The position vector of an object at any time $t$ is given by $3 t^2 \hat{i}+6 t \hat{j}+\hat{k}$. Its velocity along $y$-axis has the magnitude

A vector has magnitude and direction. Does it have a location in space ? Can it vary with time ? Will two equal vectors $a$ and $b$ at different locations in space necessarily have identical physical effects ? Give examples in support of your answer.

When the average and instantaneous accelerations are equal ?

A man on a rectilinearly moving cart, facing the direction of motion, throws a ball straight up with respect to himself

A girl riding a bicycle with a speed of $5\,ms^{-1}$ towards north direction, observes rain falling vertically down. If she increases her speed to $10\,ms^{-1}$, rain appears to meet her at $45^o$ to the vertical. What is the speed of the rain ? In what direction does rain fall as observed by a ground based observer ?

The displacement of a particle from a point having position vector $2 \hat{i}+4 \hat{j}$ to another point having position vector $5 \hat{i}+1 \hat{j}$ is ........ units