# AP Physics 1: 1.5 System Interactions and Changes

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AP Physics 1: 1.5 System Interactions and Changes. How much energy is expended in one lap?

AP Physics 1 | System Interactions and Changes |

Language | English Language |

Science Practice 4 | Using data collection strategies |

### Transcript

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

you logged your workout for the week or a month

If the track has a radius of one hundred meters

and the block track surface has a kinetic coefficient of

friction of zero point to how much energy did you

expend in one lap and hear the pencil answers All

this funky letter writing Well first of all we have

to find a new personal trainer pushing a wooden block

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

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

get us in shape huh Well to complete the calculation

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

which defines the relationship between work and energy Yeah Wow

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

force times distance And in our case here the force

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

of kinetic friction equals the coefficient of friction times mass

times gravity to determine the work done we just need

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

a circle we need to know the circumference to calculate

the distance traveled We know that the radius of the

circle is a hundred meters so we just double it

Multiply that by pi to get the circumference Remember the

formula empire Okay Lookit our potential answers We can see

that pie is included in the final results so we

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

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

in the Numbers work equals point 2 times ten kilograms

times nine point eight meters per second squared times two

hundred py meters Which gives us an answer of three

thousand nine hundred twenty pie Jules well if we convert

jewels to kill a jules will get an answer of

three point nine Two pi killa jewels So option a

is the correct answer Now on to the next question

If we only go to the gym three times a

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