<span>The relative hardness of a mineral
can be tested by the Moh’s scale or the mineral hardness. The Moh’s scale can
be characterized by the ability of the mineral to resist scratch resistance by
scratching a harder or softer mineral. It has a scale of 1 to 10 where 1 being
the softest and 10 being the hardest. The relative hardness of a mineral can
best be tested by scratching the mineral across a glass plate. The answer is
letter A. </span>
Answer:
a) fr = 266.92 N, fy = 1300 N, b) μ = 0.36
Explanation:
a) This is a balancing act.
Let's write the rotational equilibrium relations, where the turning point is the bottom of the ladder and the counterclockwise rotations are positive
-w x - W x₂ + R y = 0 (1)
usemso trigonometry to find distances
cos 60.08 = x / 7.5
x = 7.5 cos 60.08
x = 3.74 m
fireman
cos 60.08 = x₂ / 4
x2 = 4 cos 60
x2 = 2 m
wall support
sin 60.08 = y / 15
y = 15 are 60.08
y = 13 m
we substitute in equation 1
R y = w x + W x2
R = (w x + W x2) / y
R = (500 3.74 +800 2) / 13
R = 266.92 N
now let's write the expressions for the translational equilibrium
X axis
R -fr = 0
R = fr
fr = 266.92 N
Y Axis
Fy - w-W = 0
fy = 500 + 800
fy = 1300 N
b) ask the friction coefficient
the firefighter's distance is
cos 60.08 = x₃ / 9.00
x₃ = 9 cos 60
x₃ = 5.28 m
from equation 1
R = (w x + W x₃) / y
R = 500 3.74 + 800 5.28) / 13
R = 468.769 N
we saw that
fr = R = 468.769
The expression for the friction force is
fr = μ N
in this case the normal is the ratio to pesos
N = Fy
N = 1300 N
μ N = fr
μ = fr / N
μ = 468,769 / 1300
μ = 0.36
The maximum speed of the donkey is 10.72m/s
The question is based on the principle of motion in one dimension and hence formulas of motion in one dimension can be applied.
It is given that donkey attains an acceleration of 1.6 m/s^2
The time taken to accelerate to given speed is 6.7 seconds
We use the formula v=u + at to find the fastest speed
v is the final or maximum speed
u is the initial speed which in this case is 0 as the donkey is at rest
a is the acceleration of the donkey
t is the time taken in seconds
v = u + at
v= 0 + 1.6 x 6.7
= 10.72 m/s
Hence the donkey obtains the speed of 10.72 m/s
For further reference:
brainly.com/question/24478168?referrer=searchResults
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Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass
Answer:
Replacement-Level Fertility
Another important population characteristic that differ btw develop nation and developing nations is relates to births is replacement-level fertility. Replacement-level fertility is the fertility rate that will result in the replacement of the parents in the population. Again, in an ideal world, the human replacement-level fertility rate would be exactly two. This would mean that each couple would produce two offspring that would replace them in the population. If this occurred, then the human population would stay at a stable rate
