Re: Mechanical Aptitude Test

On Oct 23, 4:59 pm, "HDRDTD" <HDR...@xxxxxxxxxxx> wrote:
"Robatoy" <Counterfit...@xxxxxxxxx> wrote in message

news:1193166270.929665.176900@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Oct 23, 1:26 pm, Chris Friesen <cbf...@xxxxxxxxxxxxx> wrote:
Joe AutoDrill wrote:
http://www.forddoctorsdts.com/quizzes/MechanicalAptitude.php

I scored a 430...
Share your score with us... No shame or bragging rights, just a fun
test.

Fun little test. I got 480.

Their answer to #16 is wrong. Since the ropes are angled somewhat the
actual force would be more than 50kg. (And besides, kg are a unit of
mass, not force. The actual force would be a bit more than 9.8 * 50
Newtons.)

I too think their answer in #31 is wrong, and some of their electrical
symbols are a bit funky.

I got wrong the pipe one wrong. I expect that Bernoulli's principle
means that the pressure is lower in the narrower section.

I also got the "naturally aspirated engine" one wrong. I said it was
suction from the piston, but really that wouldn't cause anything to
happen without atmospheric pressure pushing it in, so I guess I can't
complain.

Chris

Ditto in score (480) and ditto in complaints.
Without the piston creating a (partial) vacuum, the atmosphere could
NOT push in the air....and the piston down.
Got the pipe one wrong too.

Again, this one is debatable as both 'Suction' and 'Atmospheric Pressue' are
valid answers.

As the piston goes down, it results in lowering the air pressure inside the
chamber. Thus there is now a difference in pressure between inside the
chamber and outside. It's this difference in air pressure that results in
air flowing into the chamber.

Of course the piston going down creates a lower pressure in the chamber,
which results in 'sucking' the air in.

Both answers are correct.

No they are not.
Atmospheric pressure is 14.6 PSIA A little over 14 psi over nothing.
Nothing (vacuum) is the default.
The downward pull of the piston is created by a mechanical input.
(Flywheel, whatever)
The atmosphere simply fills that void...it surely does not CREATE the
vacuum.

.

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