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

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 $B$ ?

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.

What can you say about the motion of an object if its speedtime graph is a straight line parallel to the time axis ? 

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 ?