$A$ ball is thrown vertically upward from a location and returns to the same location. Which of the following statements are correct?
$(a)$ Distance travelled by the ball can be zero.
$(b)$ Displacement of the ball is zero.
$(c)$ Average velocity of the ball is zero.
$(d)$ Acceleration of the ball is zero.

State whether the following statements are true or false:
$(a)$ An object can have acceleration even when its velocity is zero.
$(b)$ If the acceleration of a moving object is constant,the direction of its velocity must remain the same.
$(c)$ The speed of an object can never be zero.

$A$ car is moving along a straight line,say $OP$ in the given figure. It moves from $O$ to $P$ in $18\; s$ and returns from $P$ to $Q$ in $6.0\; s$. What are the average velocity and average speed of the car in going from $O$ to $P$ and back to $Q?$

$A$ particle starts from rest and traverses a distance $l$ with uniform acceleration,then moves uniformly over a further distance $2l$ and finally comes to rest after moving a further distance $3l$ under uniform retardation. Assuming the entire motion to be rectilinear,the ratio of the average speed over the journey to the maximum speed on its way is: (in $/5$)

Look at the graphs $(a)$ to $(d)$ carefully and state,with reasons,which of these cannot possibly represent one-dimensional motion of a particle.

For a particle showing motion under the force $F = -5(x - 2)^2$,the motion is .......