Motion in a Straight Line PYQs

The following plots show variation of velocity (v) with time (t) of a ball thrown vertically upward, and falling back. Which of the following plots is/are correct?

A toy car with charge q moves on a frictionless horizontal plane surface under the influence of a uniform electric field $\vec{E}$. Due to the force q$\vec{E}$, its velocity increases from 0 to 6 m/s in one second. At that instant the direction of the field is reversed. The car continues to move for two more seconds under the influence of this field. The average velocity and the average speed of the toy car between 0 to 3 seconds are:

An object is thrown vertically upward with some speed. It crosses two points p, q which are separated by h metre. If tₚ is the time between p and highest point and coming back, and t$_q$ is the time between q and highest point and coming back, relate acceleration due to gravity g, tₚ, t$_q$ and h.

A ball is thrown vertically upward. It has a speed of $10\,\text{m/s}$ when it has reached one half of its maximum height. How high does the ball rise? (Take $g = 10\,\text{m/s}^2$)