By Newton's second law, the net vertical force acting on the object is 0, so that
<em>n</em> - <em>w</em> = 0
where <em>n</em> = magnitude of the normal force of the surface pushing up on the object, and <em>w</em> = weight of the object. Hence <em>n</em> = <em>w</em> = <em>mg</em> = 196 N, where <em>m</em> = 20 kg and <em>g</em> = 9.80 m/s².
The force of static friction exerts up to 80 N on the object, since that's the minimum required force needed to get it moving, which means the coefficient of <u>static</u> friction <em>µ</em> is such that
80 N = <em>µ</em> (196 N) → <em>µ</em> = (80 N)/(196 N) ≈ 0.408
Moving at constant speed, there is a kinetic friction force of 40 N opposing the object's motion, so that the coefficient of <u>kinetic</u> friction <em>ν</em> is
40 N = <em>ν</em> (196 N) → <em>ν</em> = (40 N)/(196 N) ≈ 0.204
And so the closest answer is C.
(Note: <em>µ</em> and <em>ν</em> are the Greek letters mu and nu)
You traveled a distance of 620.075 meters if it takes you 8.5 seconds to stop.
<u>Given the following data:</u>
- Initial velocity, U = 31.3 m/s
We know that acceleration due to gravity (a) for an object is equal to 9.8 meter per seconds square.
To find the distance traveled, we would use the second equation of motion:
Mathematically, the second equation of motion is given by the formula;

Where:
- S is the distance travelled.
- u is the initial velocity.
- t is the time measured in seconds.
Substituting the parameters into the formula, we have;

<em>Distance, S</em><em> = </em><em>620.075 meters.</em>
Therefore, you traveled a distance of 620.075 meters if it takes you 8.5 seconds to stop.
Read more: brainly.com/question/8898885
The frequency, f, of a wave is the number of waves passing a point in a certain time. We normally use a time of one second, so this gives frequency the unit hertz (Hz), since one hertz is equal to one wave per second.
This number has 3 sig figs.