Answer to Question #165574 in Mechanics | Relativity for Onyi

Question

A bottle opener requires that a force of 25N must be applied to the handle in other to lift a bottle cap 0.90cm the bottle cap has a VR of 800 and an effeciency of 75%. What force is applied to the bottle cap?. How far does the handle of the opener moves?

Answer 1

Given quantities: $F = 25N$ $h = 0.9cm = 9*10^{-3}m$ $\eta=0.75$

VR - vertical radius $R = 0.8cm$

$\eta = \large\frac{A_{useful}}{A_{total}}$ $= \large\frac{F*h}{F_2*R}$ $\to F_2 = \large\frac{Fh}{R\eta}=\frac{25*9*10^{-3}}{8*10^{-3}*0.75}$ = 37.5N