A stone is tossed from the window of a building at an angle of \(25^{\circ}\) to the horizontal and with and initial speed of \(15 m / s\). If the stone is in flight for \(3.0 s\), how tall is the building? \(\left[g=9.8 m / s ^{2}\right]\).
A. \(2 m\) B. \(20 m\) C. \(23 m\) D. \(25 m\)
Correct Answer: D
Explanation
Let \(s_{y}=u_{y} t-1 / 2 g t^{2}\) $$ \begin{aligned} u_{y} &=u \sin \theta \\ s y &=(u \sin \theta) t-1 / 2 \times g t^{2} \\ s_{y} &=(15 \sin 25) \times 3-\frac{1}{2} \times 9.8 \times 3^{2} \\ s_{y} &=19.018-4.4145 \\ s_{y} &=25.127 \approx 25 m \end{aligned} $$
