ShmoopTube

00:00

Thank you We sneak and he was your shmoop du

00:05

jour Brought to you by three houses If ours had

00:08

plumbing and running water well we'd never leave Well maybe

00:11

for food Wade leave for food This dominant tree houses

00:16

are checking the following diagram and passage right here Here's

00:19

you rocks lunch right Your tree house has a sweet

00:22

system for bringing up food without making you decent Your

00:25

ladder A string connects two baskets over a massless pulley

00:30

basket Arrests at ground level and basket b is at

00:32

your front patio Yes You have a patio It's that

00:35

sweet when your mom comes by and puts lunch in

00:37

the lower basket you at rocks to basket be in

00:39

orderto lift basket a heavier basket falls and lighter taste

00:44

Your basket rises while our lunch is served We'll assume

00:48

that the police frictionless that basket a has a massive

00:51

two kilograms and basket b has a total mass of

00:54

six kilograms How fast as basket egg and your lunch

00:58

accelerate and hear the potential answers How many meters per

01:02

second squared Whoa This sounds like it might just be

01:06

the tree house of our dreams But before we hire

01:09

movers let's think about what's going on in his police

01:11

system Gravity is pulling down word on each basket and

01:14

the tension on the ropes is pulling upward and the

01:17

acceleration upward for basket a is the same as the

01:20

acceleration downward for basket b force diagrams Great tool here

01:25

if we were growing up and look a little something

01:27

like this yeah pretty cool huh So looking at the

01:31

diagram we can see that the net force of basket

01:33

a is tension minus mass times gravity and it's also

01:38

equal to mass times acceleration Well the net force of

01:41

basket b is similar but with basket be The acceleration

01:45

is a negative number because the basket is moving away

01:48

from us The equation for basket is expressed a positive

01:52

number because lunch headed towards us is always that positive

01:55

thinking Now we can solve for acceleration You subtract the

01:59

first equation from the second and solve for x And

02:11

when we do that we find that the correct answer

02:14

is b Well pulley systems are everywhere They're used on

02:18

ships elevators especially on physics test So learn this Oh 00:02:26.066 --> [endTime] snap

Full Transcript