The distance-time graph of a body is a straight line inclined to the time axis. The body is in:

$A$ body is moving along a circular path of radius $R$. Find the displacement of the body when it completes half a revolution.

$(a)$ Write differences between speed and velocity.
$(b)$ The speed of a moving object is $x \ m \ s^{-1}$. Its velocity is $y \ m \ s^{-1}$. What is the similarity observed?

From the given $v-t$ graph (Fig.),it can be inferred that the object is

Give an example of an accelerated body,moving with a uniform speed.

$A$ piece of stone is thrown vertically upwards. It reaches its maximum height in $3 \ s$. If the acceleration of the stone is $9.8 \ m s^{-2}$ directed towards the ground,calculate the initial velocity of the stone with which it is thrown upwards. Find the maximum height attained by it.