1. A rock is thrown from the roof of a building, with an initial velocity of 10 m/s at an angle of 30 degrees above the horizonal. The rock is observed to strike the ground 43 m from the base of the building. What is the height of the building?(adsbygoogle = window.adsbygoogle || []).push({});

This is what I did:

First I set my origin at the top of the building so the height would be in the negative direction

Vxi = 10 cos 30 = 8.66 m/s

Vyi = 10 sin 30 =5 m/s

Xxf - Xxi = 1/2( Vi-Vf)T

43-0 = 1/2 (8.66 + 8.66)T

43 = 8.66T

4.97 s = T

Vyf = 5 m/s -(9.8 m/s^2)(4.97s)

Vyf = -43.61 m/s

Yf-Yi = 1/2(Vi + Vf)T

Yf = 1/2(5 -43.61)4.96

Yf = -95.75 m

What I was wondering is if I found Time which is T and the height correctly?

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# Homework Help: Engineering physics problem help

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