A rod moves freely between the horizontal floor and the slanted wall. When the end in contact with the floor is moving at v, what is the speed of the end in contact with the wall?
Answer Choices
A. v \frac{\sin \theta}{\cos (\alpha-\theta)}.
B. v \frac{\sin (\alpha-\theta)}{\cos (\alpha+\theta)}.
C. v \frac{\cos (\alpha-\theta)}{\sin (\alpha+\theta)}.
D. v \frac{\cos \theta}{\cos (\alpha-\theta)} \cdot
E. v \frac{\sin \theta}{\cos (\alpha+\theta)}.
