Abdul,while driving to school,computes the average speed for his trip to be $20 \, km \, h^{-1}$. On his return trip along the same route,there is less traffic and the average speed is $40 \, km \, h^{-1}$. What is the average speed (in $km \, h^{-1}$) for Abdul's trip?

$A$ 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?

An artificial satellite is moving in a circular orbit of radius $42250 \, km$. Calculate its speed (in $m s^{-1}$) if it takes $24 \, h$ to revolve around the Earth.

When will you say a body is in $(i)$ uniform acceleration? $(ii)$ nonuniform acceleration?

An object has moved through a distance. Can it have zero displacement? If yes,support your answer with an example.

State which of the following situations are possible and give an example for each of these:
$(a)$ An object with a constant acceleration but with zero velocity.
$(b)$ An object moving with an acceleration but with uniform speed.
$(c)$ An object moving in a certain direction with an acceleration in the perpendicular direction.