Two cars $A$ and $B$ have their displacement-time graph as given below. Which car has a greater velocity?

$(a)$ Define circular motion.
$(b)$ "Uniform circular motion is an accelerated motion". Justify this statement with reason.
$(c)$ An artificial satellite is moving in a circular orbit of radius $42250 \, km$. Calculate its speed if it takes $24 \, h$ to revolve once around the Earth.

Four cars $A$,$B$,$C$ and $D$ are moving on a levelled road. Their distance versus time graphs are shown in the figure. Choose the correct statement.

$(a)$ Define uniform circular motion.
$(b)$ Ram goes for a morning walk in a circular park daily. He completes one revolution of the park in $4$ minutes. Find his speed if the diameter of the park is $420\, m$.
$(c)$ Draw velocity$-$time graph for uniform motion along a straight line. How can you find the distance covered by a body from this graph?

Name the physical quantities denoted by:
$(i)$ The slope of the distance$-$time graph.
$(ii)$ The area under a velocity$-$time graph.
$(iii)$ The slope of a velocity$-$time graph.

Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of $10 \, ms^{-1}$. It implies that the boy is