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)
Answer:
This property could be used to create technologically-advanced tools or machines that could easily locate the mineral deposits.
Explanation:
Mineral deposits are hard to find, unless you have the skill or the proper tools in locating them. This is the reason why many people are mining in order to explore the different areas where they could find these deposits.
If one would consider the property of minerals, such as being good conductors of heat and electricity,<u> then they could create a tool or machine that would aid in their exploration.</u> Inventors could probably come up with a sensitive detector which signals when it reaches an area of high heat and electric conductivity. Since most minerals such as <em>gold, silver, copper, galena, bornite </em>and the like have this property, then miners will have a lesser amount of time looking for them.
If this technology will be implemented, though, regulation policy must be strictly implemented because it might lead to<em> over-mining</em> thus leading to the depletion of mineral deposits.
Explanation:
Given that,
Distance, s = 47 m
Time taken, t = 8.6 s
Final speed of the truck, v = 2.3 m/s
Let u is the initial speed of the truck and a is its acceleration such that :
.............(1)
Now, the second equation of motion is :
Put the value of a in above equation as :
u = 8.63 m/s
So, the original speed of the truck is 8.63 m/s. Hence, this is the required solution.
