Answer:
μ = 0.18
Explanation:
Let's use Newton's second Law, the coordinate system is horizontal and vertical
Before starting to move the box
Y axis
N-W = 0
N = W = mg
X axis
F -fr = 0
F = fr
The friction force has the formula
fr = μ N
fr = μ m g
At the limit point just before starting the movement
F = μ m g
μ = F / m g
calculate
μ = 34.8 / (19.8 9.8)
μ = 0.18
A theorem can be proven (from axioms or prior theorems), using logic.
A hypothesis can be supported by evidence. The more evidence in support of the hypothesis, the more likely the hypothesis is to be correct. However, you’re always at the mercy of contrary evidence appearing in the future, to reduce the likelihood or even invalidate a hypothesis.
A (mathematical) proof suffers no such vulnerability to future evidence, as long as you hold the axioms of the theory to be true, and as long as there was no flaw in the construction of the proof.
Answer:
Explanation:
given,
side slope = 1 : 1
hydraulic depth(y) = 5 ft
bottom width (b)= 8 ft
x = 1
Q = 2,312 ft³/s
n = 0.013
slope of channel = ?
R = 4.69 m
using manning's equation
S = 0.406
Answer:
a) 
& 
b) 
c) 
Explanation:
Given:
mass of the book, 
combined mass of the student and the skateboard, 
initial velocity of the book, 
angle of projection of the book from the horizontal, 
a)
velocity of the student before throwing the book:
Since the student is initially at rest and no net force acts on the student so it remains in rest according to the Newton's first law of motion.
where:
initial velocity of the student
velocity of the student after throwing the book:
Since the student applies a force on the book while throwing it and the student standing on the skate will an elastic collision like situation on throwing the book.
where:
final velcotiy of the student after throwing the book
b)
c)
Since there is no movement of the student in the vertical direction, so the total momentum transfer to the earth will be equal to the momentum of the book in vertical direction.
Answer:
A, B, and C are good reasons for my friend not to worry
Explanation:
The following reasons are reason not to worry
A. The only way to lose additional partial credit on a hint is by using the "give up" button or entering incorrect answers. Leaving the question blank will not cost you any credit (Regardless of whether you open a link or not, you will lose credit if you enter a wrong answer or if you give up on a question by hitting the "give up" button. Even after opening a hint, you can leave the question blank if the hint does not provide relevant hints or if the hint brings up more question. Once the question is left blank, you do not lose additional partial credit)
B. As an incentive for thinking hard about the problem, your instructor may choose to apply a small hint penalty, but this penalty is the same whether the hint simply gives information or asks another question (In a situation where you decide to use a hint, the instructor may have put a penalty for using the hint, so whether it asks a question or help in the solution of the question, as long as the hint is consulted, the hint penalty still applies)
C. Getting the correct answer to the question in a hint actually gives you some partial credit, even if you still can't answer the original question (An advantage of using hint is that you get some partial credit for using it if you answer the hint question correctly and fails to answer the original question)
