(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Take up as positive. A rock is projected from the edge of the top of a building with an initial velocity of 16.5 m/s at an angle of 40 degrees above the horizontal. The rock strikes the ground a horizontal distance of 82m from the base of the building. The acceleration of gravity is 9.8m/s2. Assume the ground is level and that the side of the building is vertical. Neglect air friction.

How tall is the building? Answer in units of m.

2. Relevant equations

delta X= Vxt

Vy= V0y + ayt

Yf-yi= V0yt + 1/d ayt2

3. The attempt at a solution

For this problem, I already found the horizontal component of the rock's velocity when it strikes the ground and the time the rock stays airborne. However, I'm not quite sure how to find the height of the building. I tried doing it this way: Use equation 3, substituting 0 for yi (ground level) and the ycomponent of velocity, and the acceleration as -9.8 to solve for Yf. Is my process right? Because when I solve for Yf, I get 275.0343353, which according to quest, is wrong.

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# Projectile motion- height of building

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