Answer: B. Concrete
Explanation:
Let N = reacting force pressing the bodies in context together (units in Newtons),
The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.
We need to start by finding the weight of the piece of wood.
friction is given by
f = μN
The value of f is 22.5,
and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.
22.5 = 75. 0.30
Putting the values into the equation: 22.5 = 0.30N.
Divide both sides by 0.30 to find the value of N:
N= 22.5/0.3 = 75
Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.
To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:
46.5 = µ(75).
Divide both sides by 75 to isolate μ.
The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).
Answer:
Magnetic activity and sunspots are in a proportional relationship.
Explanation:
From the graph, as one increases, so does the other, thus we describe the relationship as proportional.
Other than that, all of your other answers seem correct.
He worked with Euler on elasticity and the development of the Euler-Bernoulli beam equation.
I think it’s A I got that off the information I got in the internet
The final temperature of the block is 
Explanation:
The amount of thermal energy Q supplied to a substance is related to the increase in temperature of the substance,
, according to the equation

where:
m is the mass of the substance
is the specific heat capacity of the substance
In this problem, we have:
m = 1.2 kg is the mass of the block
is the amount of energy supplied to the block
is the specific heat capacity of the block
Solving for
, we find the increase in temperature:

And since the initial temperature was

The final temperature will be

Learn more about specific heat capacity:
brainly.com/question/3032746
brainly.com/question/4759369
#LearnwithBrainly