Question

A 15.0 kg block is pulled by a horizontal force of 30.0 N along a rough horizontal surface at constant velocity. What is the coefficient of friction?

Answer 1

What is muk?

Answer 2

\[30 - \mu _{k}*N =0\]
\[mg=N\]
\[30 - \mu _{k}*mg =0\]

Answer 3

better?

Answer 4

ooh ok.. thats better.

Answer 5

So 30 - muk * 15.0=0
right
since mg is equals to newton or nope? @Algebraic!

Answer 6

yep, you're right so far...

Answer 7

you forgot 'g' actually...

Answer 8

m*g

Answer 9

you just have mass... need a '9.8 m/s^2 ' in there too.

Answer 10

do wee need to solve the gravity or nope? because its saying "pulled by a horizontal force"
Do you know what i mean right?

Answer 11

solve:
\[30 - \mu _{k}*15*9.8 = 0\]
for mu k

Answer 12

muk= -4425? @Algebraic!

Answer 13

30/(15*9.8)

Answer 14

use your algebra skills. this is what you trained for.

Answer 15

Sorry. xD
I got 0.20
My teacher gave us the
gravity=9.81

Answer 16

yes .204 is right.

Answer 17

:)

Answer 18

just making sure:
the formula is \[F=\mu*N \]??
and then why you put equals zero at the end?
i just want to know?

Answer 19

the 'formula' is F=ma
which means net force = ma
which means add up all the forces and the sum is ma
here there's two forces, the applied force and the friction force
and they add up to the acceleration (which is zero) times the mass...
Force from friction is muk*Normal
since it's a 'flat' surface Normal = mg
so:
applied force - friction force = 15*0
30 - muk*mg =0

Answer 20

Thank you.
So when its asking for flat surface or what ever is that called it will be Normal = mg
the Mass times the gravity right?

Answer 21

yes

Answer 22

thank you

Answer 23

sure!