What conclusion can you draw from the displacement$-$time graph of a body shown below?

State the type of motion represented by the given graph.

$(a)$ Differentiate acceleration from velocity.
$(b)$ Can a body have acceleration without change in magnitude of velocity? Explain with an example.
$(c)$ $A$ motor boat starting from rest on a lake accelerates in a straight line at a constant rate of $3 \, m s^{-2}$ for $8 \, s$. How far does the boat travel during this time?

Can a body have constant speed and still be accelerating?

Draw velocity-time graphs for the following situations:
$(i)$ When a body is moving with uniform velocity.
$(ii)$ When a body is moving with variable velocity,but uniform acceleration.
$(iii)$ When a body is moving with variable velocity,but uniform retardation.
$(iv)$ When a body is moving with variable velocity and variable acceleration.

What is the average velocity of a particle when it returns to the starting point? Can its average speed be zero?