# AP Physics 1: 3.1 System Interactions and Changes

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AP Physics 1: 3.1 System Interactions and Changes. What is the coefficient of friction between the biscuit and the court?

AP Physics 1 | System Interactions and Changes |

Language | English Language |

Science Practice 5 | Performing data analysis |

### Transcript

end of a narrow lane A grid with various scores

is located at the other end He uses a broom

to push a pot called a biscuit down the lane

If grandpa shmoop gives the four kilogram biscuit an initial

speed of five meters per second and the biscuit comes

to rest after ten meters what is the coefficient of

friction between the biscuit and the court And here the

potential answers All right well this could get complicated if

we let it The biscuit starts off with kinetic energy

and kinetic energy equals one half mass times velocity square

The coefficient of friction then goes to work on the

puck taking that kinetic energy away Well looks like this

is a job for the work energy the're Um the

work energy tour means that the work done by a

force becomes the kinetic energy of the object of forces

working on here's The equation In this case the biscuit

is losing energy so the changing kinetic energy is negative

and the work is negative as well So in our

question here the work done by friction is equal to

the change in kinetic energy Equation For the force of

kinetic friction is mass times gravity times that coefficient And

since we're working here we have to include displacement represented

by x Well now we can solve for the coefficient

you and we can see that as we solve this

equation we don't actually use the objects mass It cancels

itself out Coefficient mu equals velocity squared divided by two

tons Gravity times displacement So when we plug in those

numbers we get an answer of one eighth So option 00:02:02.49 --> [endTime] a Yeah that's it that's the correct answer