We know that the initial velocity $u$ of the projectile is $-4 \, \mathrm{m/s}$ (upward), the acceleration due to gravity $g$ is $9.8 \, \mathrm{m/s}^2$ (downward), and the time $t$ it takes for the projectile to hit the ground is $4 \, \mathrm{s}$. We can use the
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