If the displacement$-$time graph for a particle is parallel to time axis, what is the velocity of the particle ?

$(a)$ Define acceleration.

$(b)$ A stone describes a circular path with a constant speed. State the type of motion of the stone.

Can a body have constant speed and still be accelerating ?

Write true or false for the following statements

The motion in animals is called locomotion. Mechanics deals with the motion of non$-$living objects.

A body moving with uniform acceleration has velocities $20 \,m s ^{-1}$ and $30\, m s ^{-1}$. when passing two points $A$ and $B$. Then the velocity midway between $A$ and $B$ is