Question

Find the mechanical advantage of a pipe vise if it has a handle diameter of 16 in., a screw diameter of 0.75 in., and a screw pitch of 0.125 in.


FR * pitch = FE * 2pi * r
MA = 2 pi r / pitch = 2 pi (d/2) / pitch = pi d / pitch
= pi * 16 in / 0.125 in = 128 pi = 804.248 = 804

how many significant figures should my answer be? 2 or 3?

Answer 1

your answer is correct! I think that better is to round off to the nearest hundred, namely:
MA= 800

Answer 2

actually, the answer should be 400... but I am not sure how to get that answer

Answer 3

I'm pondering...

Answer 4

maybe we have to consider the efficiency of the screw which can be 0.5

Answer 5

if we have to consider the efficiency of the screw, then the requested advantage is:
\[\Large MA = \frac{{\pi D}}{{pitch}} \times \eta \]
where \eta is the efficiency of the screw
Please keep in mind that a screw is a simple machine, so it has an own efficiency

Answer 6

of course, we have:
\[\Large \eta = 50\% \]

Answer 7

@Michele_Laino MA = (π * 16 in / 2) * 50% = 12? how do I get 400?

Answer 8

Sorry, I got this:
\[MA = \frac{{3.14 \times 16}}{{0.125}} = 401.92\]

Answer 9

why do we use 16 in and not .75 in ?

Answer 10

@Michele_Laino