Question

The force required to drag several objects across a floor was measured. Calculate the µK for these objects.

Block Weight Friction µK




A 150 lb 30 lb




B 20.0 N 5.0 N




C 1,500 lb 60 lb





(NOTE: I don't want want you to just give me the answer, I want to know how to work it.)

Answer 1

Step-by-step explanation:

Case-A

Block weight
`W=150\ lb`

Friction Force
`f=30\ lb`

and friction force is

`f=\mu _kN`

where N=normal reaction (Usually equals to weight)

`\mu _k=(30)/(150)`

`\mu _K=(1)/(5)=0.2`

Case-B

Block weight
`W=20\ N`

Friction Force
`f=5\ N`

`\mu _k=(f)/(N)`

`\mu _k=(5)/(20)=(1)/(4)`

`\mu _k=0.25`

Case-C

Block weight
`W=1500\ lb`

Friction Force
`f=60\ lb`

`\mu _k=(f)/(N)`

`\mu _k=(60)/(1500)`

`\mu _k=0.04`