Scenes the chair wheels are up the person is rolling backwards and if the wheels were down then the person would go forwards
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Answer:
So coefficient of kinetic friction will be equal to 0.4081
Explanation:
We have given mass of the block m = 0.5 kg
The spring is compressed by length x = 0.2 m
Spring constant of the sprig k = 100 N/m
Blocks moves a horizontal distance of s = 1 m
Work done in stretching the spring is equal to 
This energy will be equal to kinetic energy of the block
And this kinetic energy must be equal to work done by the frictional force
So 


So coefficient of kinetic friction will be equal to 0.4081
There’s no picture and what’s the length?
6.3 That Would be the I answer I think but Check on Google For the formula
By someone wearing them doing some exhilarating thing