For a ball thrown vertically upwards and returning to the ground, the velocity-time graph:

1. The ball leaves the hand with initial velocity $u$, so at $t=0$ the velocity is not zero. 2. The graph therefore starts above the origin, not at it. 3. Gravity decelerates the ball according to $v=u-gt$, so the line falls steadily. 4. At $t=\dfrac{u}{g}$ the velocity reaches zero, which is the highest point of the flight. 5. Beyond that the ball falls, so velocity grows in the opposite direction and the line continues below the axis. _Source: NECTA CSEE 2021 Physics 031, Question 1: Multiple Choice, item (iv)_