ShmoopTube

00:00

Thank you We use her shmoop du jour Brought to

00:05

you by pistons Yes Detroit's famous basketball team has won

00:08

three championships and his proud reflection of the city Wait

00:12

this is ap basketball prep isn't it Okay Well onto

00:16

the physics a student designed the hydraulic press with two

00:21

the first pissed and has an area's Five meters squared

00:24

and is depressed forty centimeters by the force of fifty

00:28

newtons How much work is done on the second kissed

00:31

in which has an area of ten meters squared by

00:33

the fluid when the first piston is depressed all right

00:37

there's Potential answers right Answer this We need to employ

00:42

pascal's principle Talked about plays pascal before but we don't

00:45

mind talking about him again Because while seriously plays pascal

00:48

coolest name ever telling a gunslingers or fashion anyway pascal

00:55

stated the change in pressure and enclosed fluid is transmitted

00:58

equally and unchanged Toe all points within that fluid This

01:02

makes sense since you can't compress the liquid it's Just

01:05

not possible to make a leader of water shrink down

01:07

Tto only take up half a litre of volume Not

01:10

even the strongest person alive Sorry arnie If you squeeze

01:14

In close fluid pressure of you're squeezing will be allied

01:17

everywhere within that container Want a real life example Well

01:21

it's going to go The old toilet plunger let's say

01:24

our baby sister flushes are physics homework in calm rational

01:28

physicists are first course of action is to see if

01:30

we can trade her in for a puppy Regardless of

01:33

whether or not our sister is getting bids off there

01:36

on ebay way Still need to get the toilet working

01:38

We'll take our trusty plunder and apply force Since the

01:41

toilet's stopped we haven't contained fluid A force to be

01:45

applied The plunger is transmitted through the fluid without diminishing

01:48

Because the walls of the piper strong enough to resist

01:50

the pressure Most of the force is applied to the

01:52

physics homework forcing it through the pipe van into the

01:55

sewers It means our genius will continue to go unrecognized

02:00

What is all this relate to our problem Well it's

02:02

like it's Time to do some math first we need

02:04

to find the pressure created Pressure equals force divided by

02:08

area force of fifty Newton's has supplied the first piston

02:11

which has an area of five meters squared The pressure

02:14

Created by the first fists and equals ten scouts to

02:17

find the force acting on the second pissed And we

02:19

just re arrange that for me Force equals pressure times

02:22

area with a pressure of ten pascal's in an area

02:25

of ten meters square The force acting on the second

02:27

pissed and equals one hundred years We're doing some good

02:30

work here so we can work let's calculate that next

02:33

that's what we call a sick way people smoother then

02:36

blaise pascal himself work is force multiplied by distance so

02:40

we need to know how high the second pissed and

02:42

will rise do that We couldn't figure out how much

02:45

water is being displaced by the first pistol volume equals

02:49

area times distance which in this case is a change

02:51

in height Like in the numbers we find the displaced

02:55

volume equals two cubic meters and that same volume is

02:58

what who's the second pistons The change in high that

03:01

the second pissed and equals the volume of water divided

03:04

by the area long last we can calculate the work

03:07

done quickly said way back when work equals force times

03:12

distance forces one hundred newton's on the change in distance

03:15

is point two meters so the work done equals twenty

03:18

jules correct answer is that we used conservation of energy

03:22

We could've saved ourselves a whole lot of trouble by

03:24

just determining the work done on the first piston worked

03:27

on on the first piston equals fifty newness times point

03:30

four meters which surprise surprise equals twenty jules But if

03:33

we had just on that first place we wouldn't get

03:35

all the other equations and well that's no fun work 00:03:38.7 --> [endTime] Seven might have a strange idea of fun

Full Transcript