If you use a horizontal force of 30.0 N to slide a 12.0 kg wooden crate across the floor at a constant velocity, what is the normal force?

i found: μk= 0.25

Explanation:

Newton's law is split into two components along

x and y , that, using our data, give:

30 − μkRn = 0

Rn = mg = 12⋅9.81 = 117.7 ≈ 118N

So: μk = 30/118 = 0.25

Please Mark Brilliant

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )