ShmoopTube

00:00

Thank you We sneak and here's your smoke du jour

00:05

Brought to you by exercise You can go to the

00:07

gym to work out your body but you're here to

00:10

work out your mind All right Pushing a ten kilogram

00:13

block around a circular track is tiring you know although

00:16

the block it's nothing out of the experience At least

00:19

you logged your workout for the week or a month

00:21

If the track has a radius of one hundred meters

00:24

and the block track surface has a kinetic coefficient of

00:28

friction of zero point to how much energy did you

00:32

expend in one lap and hear the pencil answers All

00:36

this funky letter writing Well first of all we have

00:39

to find a new personal trainer pushing a wooden block

00:42

around a track isn't gonna get us ready for beach

00:44

season That's what we get for hiring a physicist to

00:46

get us in shape huh Well to complete the calculation

00:49

here we need to employ the work energy the're Um

00:52

which defines the relationship between work and energy Yeah Wow

00:56

that was a shock That wasn't it Now work equals

00:58

force times distance And in our case here the force

01:01

we're looking at is the force of friction The force

01:04

of kinetic friction equals the coefficient of friction times mass

01:07

times gravity to determine the work done we just need

01:10

to add distance to the equation Since we're going in

01:13

a circle we need to know the circumference to calculate

01:16

the distance traveled We know that the radius of the

01:19

circle is a hundred meters so we just double it

01:21

Multiply that by pi to get the circumference Remember the

01:24

formula empire Okay Lookit our potential answers We can see

01:29

that pie is included in the final results so we

01:32

don't have to actually figure out the exact number We

01:35

can just stick with two hundred pie now Let's Plug

01:38

in the Numbers work equals point 2 times ten kilograms

01:43

times nine point eight meters per second squared times two

01:46

hundred py meters Which gives us an answer of three

01:49

thousand nine hundred twenty pie Jules well if we convert

01:53

jewels to kill a jules will get an answer of

01:56

three point nine Two pi killa jewels So option a

01:58

is the correct answer Now on to the next question

02:01

If we only go to the gym three times a

02:03

month How much are we really paying for our monthly 00:02:06.5 --> [endTime] membership No

Full Transcript