A ball is allowed to fall onto a floor. Just before it strikes the floor, its speed is $3.0\,\text{m s}^{-1}$. Which alteration would make its speed $6.0\,\text{m s}^{-1}$ immediately before impact? Ignore any effects due to air resistance.
- ADrop the ball from double the height above the floor.
- BDrop the ball from four times the height above the floor.
- CUse a ball with double the mass.
- DUse a ball with four times the mass.