JAMB Physics 2019 Paper

Concept:The velocity ratio of a screw jack is the distance moved by the effort divided by the distance the load is lifted in one complete turn.Explanation:Given pitch $P = 0.2\,\text{cm}$ and tommy bar length $r = 23\,\text{cm}$.In one full turn, the effort moves around a circle of radius $r$.So effort distance $= 2\pi r$.The load is lifted by a distance equal to the pitch $P$.Thus, $VR = \frac{2\pi r}{P}$.Substitute the values: $VR = \frac{2\pi \times 23}{0.2}$.Simplify: $VR = \frac{46\pi}{0.2} = 230\pi$.Answer:A. $230\pi$