A boy throws a ball straight up vertically. The ball climbs to a greatest height, where it is briefly stationary, and then comes back down into his hands. Which row shows the ball’s acceleration at each stage of its motion? (Treat vertically upwards as positive. Neglect air resistance.)
- Arising: $-9.81\,\text{m s}^{-2}$, at maximum height: $0$, falling: $+9.81\,\text{m s}^{-2}$
- Brising: $-9.81\,\text{m s}^{-2}$, at maximum height: $-9.81\,\text{m s}^{-2}$, falling: $-9.81\,\text{m s}^{-2}$
- Crising: $+9.81\,\text{m s}^{-2}$, at maximum height: $+9.81\,\text{m s}^{-2}$, falling: $+9.81\,\text{m s}^{-2}$
- Drising: $+9.81\,\text{m s}^{-2}$, at maximum height: $0$, falling: $-9.81\,\text{m s}^{-2}$