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## Homework Statement

A cannonball is fired with an initial speed of 90.0 m/s at an angle 45.0 ° above the horizontal (see diagram). The cannonball strikes point A on top of a cliff 8.7 s seconds after being fired. Ignore air resistance in this problem.

How high is the cliff? (correct answer is:

**183**meters)

## The Attempt at a Solution

[tex]v_{iy}=90 sin(45)=63.63[/tex]

[tex]y=v_{iy}t+ \frac{1}{2}(a)t^2=63.63 \times 8.7 + 0.5 (9.81)\times 8.7^2 = 924.8[/tex]

But why is this wrong?

P.S. I also know that the the maximum height the cannonball reaches is 206.42 and I have already calculated that point A is 553.66 meters horizontally from the cannon. Not sure if this helps...