WAEC Physics 2017 Paper

Concept:The velocity ratio of an inclined plane is the ratio of the distance moved by the effort along the slope to the vertical distance through which the load is raised.Explanation:For an inclined plane, the effort moves through the length $L$ of the plane.The load is lifted through the vertical height $h$.By definition, $\text{Velocity ratio} = \frac{\text{Effort distance}}{\text{Load distance}} = \frac{L}{h}$.From the geometry of the plane, $\sin\theta = \frac{h}{L}$.Therefore, $\frac{L}{h} = \frac{1}{\sin\theta}$.Hence, the velocity ratio equals the inverse of $\sin\theta$, which is $\csc\theta$.Answer:$\frac{1}{\sin\theta}$Correct option: C.