While moving a 71 kg box across a horizontal floor, you find that it takes a 190 n force to get the box moving (pushing horizontally), but just a 120 n force to keep it moving at constant speed thereafter. what is the coefficient of static friction between box and floor? what is the coefficient of kinetic friction between box and floor?

μs=  0.273

μk=  0.172

Explanation:

The formula to calculate friction force is :

f = μ *N

Where:

μ :  friction coefficient

N: Normal Force

N=W  

W = m*g= 71 kg * 9.8 m/s² = 695.8 N :  weight of the box

Problem development

fs = μs*N

μs: coefficient of static friction

fs= 190 N : Static friction force

N = 695.8 N

μs= fs / N

μs=  190 N / 695.8 N

μs=  0.273

fk = μk*N

μk: coefficient of kinetic friction between box and floor

fk= 120 N :kinetic friction force

N = 695.8 N

μk= fk / N

μk= 120 N / 695.8 N

μk=  0.172

c because the action was the roller coaster reaches bottom of hill (action) reaction would be blood tends to drain away from head

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answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.