The object has acting on it the force due to gravity, so its acceleration is -9.8 ms-2.
`v=int a dt`
Now at `t = 0`, the velocity = `15\ "ms"^-1`. So `C = 15`.
So the expression for velocity becomes:
Now, we need to find the displacement, so we integrate our expression for velocity:
`s=int v\ dt`
`=int(-9.8t + 15) dt`
Now, we know from the question that when `t = 0`, `s = 0`.
This gives `K = 0`.
At time `t = 2.5`, `s = 6.875\ "m"`.
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