The speed-time graph for a car is shown is Fig.

$(a)$ Find how far does the car travel in the first $4,sec$. Shade the area on the graph that represents the distance travelled by the car during the period.

$(b)$ Which part of the graph represents uniform motion of the car ?

During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of light, that is, $3 \times 10^{8}\,m\,s^{-1}$.

Joseph jogs from one end $A$ to the other end $B$ of a straight $300\, m$ road in $2\, min$ $30\, sec$ and then turns around and jogs $100 \,m$ back to point $C$ in another $1\, min$. What are Joseph's average speeds and velocities in jogging from $A$ to $B$ ?

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 ?

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.